JP6218365B2 - Medical diagnostic imaging equipment - Google Patents

Description

  Embodiments described herein relate generally to a medical image diagnostic apparatus.

  A medical image diagnostic apparatus is an apparatus that images information in a subject (such as a fluoroscopic image, a tomographic image, and a blood flow image). Examples of the medical image diagnostic apparatus include an X-ray imaging apparatus, an X-ray CT apparatus, an MRI apparatus, and an ultrasonic diagnostic apparatus.

  For example, the X-ray imaging apparatus exposes X-rays to a subject disposed between an X-ray source and an X-ray detection unit that are arranged to face each other. Furthermore, the X-ray imaging apparatus detects X-rays that have passed through the subject and generates a medical image based on the detection result.

  An angio system is known as an example of an X-ray imaging apparatus. An angio system is used, for example, for fluoroscopy of a blood vessel form or a blood flow state of a subject into which a contrast medium is injected. The operator inserts a catheter or the like into the subject's vessel while observing the fluoroscopic image. Such radiological diagnostic techniques such as an X-ray angiography system or CT angiography (CTA) can be applied to diagnosis, treatment, drainage, supply, etc. as IVR (Interventional Radiology).

  Some X-ray imaging apparatuses such as an angio system can execute automatic brightness adjustment control. Automatic brightness adjustment control is a process for optimizing the brightness of a fluoroscopic image. In the following, the automatic brightness adjustment control may be referred to as ABC (Automatic Brightness Control) control. The X-ray imaging apparatus stores in advance a set value of a luminance level used for ABC control. The brightness level of the fluoroscopic image is adjusted based on this set value, and is reflected in the clarity and clarity of the image.

  More specifically, in the ABC control, the X-ray imaging apparatus acquires a brightness level value (for example, an average value of brightness levels) in a fluoroscopic image based on transmitted X-rays obtained by X-ray exposure. The X-ray imaging apparatus reads a preset value stored in advance and compares it with the brightness level value of the fluoroscopic image. When the brightness level value is different from the set value, the X-ray imaging apparatus changes the fluoroscopic irradiation condition (imaging condition) in fluoroscopy so that the brightness level value matches the set value. The fluoroscopic irradiation conditions include mAs indicating the product of X-ray irradiation time and tube current, tube voltage kV, and the like.

JP 2003-115399 A

  The X-ray imaging apparatus can perform fluoroscopy by changing the X-ray irradiation range. For example, the X-ray irradiation range can be narrowed. When the X-ray irradiation range becomes narrow in this way, a part of the subject that has been the X-ray irradiation range until then becomes out of the irradiation range. That is, the X-ray irradiated from the X-ray tube is partially absorbed by the X-ray diaphragm, so that the irradiation range is limited. As a result, if the portion limited by the X-ray aperture is the target of ABC control, it is determined that the brightness level of the image after the irradiation range limitation is low. If it is determined that the brightness level of the image is low in the ABC control, the imaging conditions are adjusted, and the X-ray conditions are increased so as to reach a preset brightness level.

  Moreover, the ratio of each structure contained in the irradiation range with respect to the entire irradiation range is greater after the limitation than before the irradiation range is limited. Therefore, if a structure that tends to lower the luminance is included in the irradiation range, it is determined that the luminance level is low in ABC control.

  Thus, when it is determined that the brightness level is low in the ABC control, the fluoroscopic irradiation condition is adjusted, and the X-ray condition is increased so as to reach a preset brightness level.

  As described above, if the X-ray condition is increased to adjust the luminance level by limiting the irradiation range, there is a risk of causing an increase in the local exposure amount of the subject.

  The problem to be solved by the present invention is to provide a technique capable of preventing an increase in the exposure amount of a subject in X-ray imaging.

The medical image diagnostic apparatus according to the present embodiment includes an imaging unit, an X-ray image generation unit, a first storage unit, a calculation unit, an adjustment unit, a second storage unit, and a comparison unit . The imaging unit can repeatedly image the subject by changing the X-ray irradiation range. The X-ray image generation unit generates an X-ray image based on the imaging. The first storage unit stores a first threshold value that is a preset threshold value of the pixel value. The calculation unit calculates a statistical value of the pixel value of the X-ray image. Further, calculator, said when the X-ray irradiation range is reduced in the imaging, to correspond to the reduction to reduce the range of the pixel to be calculated of the statistics. The adjustment unit adjusts an operation condition of the photographing unit so that the statistical value approaches the first threshold value. The second storage unit stores a second threshold value that is a preset threshold value of the pixel value. The comparison unit identifies the some pixels so as to exclude pixels having low pixel values based on the second threshold. The calculation unit calculates the second statistical value for the part of pixels specified by the comparison unit.

1 is a schematic block diagram illustrating an overall configuration of an X-ray imaging apparatus according to an embodiment. It is a schematic perspective view which shows an example of a structure of the X-ray diaphragm concerning embodiment. It is the schematic which shows an example of the relationship between the normal region of interest and the region of interest for partial fluoroscopy. It is a schematic block diagram which shows an example of a function structure of the X-ray detection part concerning embodiment. It is a schematic block diagram which shows a part of functional structure of the collection data process part concerning 1st Embodiment. It is a schematic flowchart explaining the flow of the 1st ABC control of the medical image diagnostic apparatus which performs fluoroscopy. It is a schematic flowchart explaining the flow of 2nd ABC control of the medical image diagnostic apparatus regarding the partial fluoroscopy in 1st Embodiment. It is a schematic block diagram which shows a part of functional structure of the display data processing part concerning 1st Embodiment. It is a schematic block diagram which shows a part of functional structure of the collection data process part concerning 2nd Embodiment. It is a schematic flowchart explaining the flow of the 1st gain adjustment of the medical image diagnostic apparatus of 2nd Embodiment which performs fluoroscopy. It is a schematic block diagram which shows a part of functional structure of the display data processing part concerning 3rd Embodiment. It is a schematic flowchart explaining the flow of the 2nd gain adjustment of the medical image diagnostic apparatus of 3rd Embodiment which performs fluoroscopy. It is a schematic flowchart explaining the flow of 2nd ABC control of the medical image diagnostic apparatus regarding the partial fluoroscopy in 5th Embodiment. It is a schematic flowchart explaining the flow of 2nd ABC control of the medical image diagnostic apparatus regarding the partial fluoroscopy in 5th Embodiment. It is a schematic block diagram which shows a part of functional structure of the collection data process part concerning 6th Embodiment. It is a schematic flowchart explaining the flow of 2nd ABC control of the medical image diagnostic apparatus regarding the partial fluoroscopy in 6th Embodiment. It is a schematic flowchart explaining the flow of 2nd ABC control of the medical image diagnostic apparatus regarding the partial fluoroscopy in 6th Embodiment. It is a schematic flowchart explaining the flow of 2nd ABC control of the medical image diagnostic apparatus regarding the partial fluoroscopy in 7th Embodiment. It is a schematic flowchart explaining the flow of 2nd ABC control of the medical image diagnostic apparatus regarding the partial fluoroscopy in 7th Embodiment. It is a schematic block diagram which shows the whole structure of the medical image diagnostic apparatus concerning 8th Embodiment. It is a schematic flowchart explaining the flow of ABC control of the medical image diagnostic apparatus in 8th Embodiment. It is a schematic flowchart explaining the flow of ABC control of the medical image diagnostic apparatus in 8th Embodiment. It is a schematic block diagram which shows a part of functional structure of the collection data process part concerning 9th Embodiment. It is a schematic flowchart explaining the flow of ABC control of the medical image diagnostic apparatus in 9th Embodiment. It is a schematic flowchart explaining the flow of ABC control of the medical image diagnostic apparatus in 9th Embodiment. It is a schematic flowchart explaining the flow of ABC control of the medical image diagnostic apparatus regarding fluoroscopy in 10th Embodiment. It is a schematic flowchart explaining the flow of ABC control of the medical image diagnostic apparatus regarding fluoroscopy in 10th Embodiment.

  The medical image diagnostic apparatus according to the first to tenth embodiments will be described with reference to FIGS.

[First embodiment]
With reference to FIGS. 1 to 8, the configuration of the medical image diagnostic apparatus according to the first embodiment will be described using an X-ray imaging apparatus as a main example.

(Overview of the entire X-ray imaging system)
FIG. 1 is a schematic block diagram showing the overall configuration of the X-ray imaging apparatus according to the first to seventh embodiments. An X-ray diagnostic apparatus 100 shown in FIG. 1 includes a bed 2, an X-ray tube 3, an X-ray diaphragm 4, and an X-ray detection unit 5. The X-ray diagnostic apparatus 100 includes an arithmetic control unit 11, an X-ray control unit 12, an aperture control unit 13, a drive control unit 14, a collection data processing unit 15, a user interface 16, a display data processing unit 17, and fluoroscopic irradiation conditions. A setting unit 18 is provided.

<User interface 16>
The user interface 16 includes a display unit 161 and an operation unit 162. The display unit 161 is configured by a display device of any form such as a CRT (Cathode Ray Tube) display or an LCD (Liquid Crystal Display). The display unit 161 displays various screens and images under the control of the arithmetic control unit 11.

  The operation unit 162 is configured by an arbitrary type of operation device or input device such as a keyboard, a mouse, a trackball, a joystick, a foot pedal, or a control panel. The calculation control unit 11 receives an operation signal output from the operation unit 162 based on the performed operation, and executes control and calculation corresponding to the operation content.

  In FIG. 1, the display unit 161 and the operation unit 162 are described separately, but they can also be configured integrally, such as a touch panel type LCD or pen tablet.

<Bed 2>
A subject P is placed on the top plate of the bed 2. The subject P is placed with its body axis direction aligned with the longitudinal direction of the top plate of the bed 2. The top plate can be moved at least in the longitudinal direction of the bed 2 (the body axis direction of the subject P) by a drive unit (not shown). The top plate may be moved in the short direction or may be rotated and moved horizontally with the subject.

<X-ray control unit 12-main control unit 121>
As shown in FIG. 1, the X-ray controller 12 includes a high voltage generator 122 that generates a high voltage, and a main controller 121 (such as a microprocessor) that controls the high voltage generator. . Although the X-ray control unit 12 has other functions than these, illustration is omitted.

  The main control unit 121 receives information on fluoroscopic irradiation conditions such as preset X-ray irradiation conditions (tube voltage kV, tube current / irradiation time product mAs) from the fluoroscopic irradiation condition setting unit 18. Further, the main control unit 121 receives an X-ray irradiation instruction signal from the operation unit 162 or the like. Based on the fluoroscopic irradiation conditions, each unit related to X-ray irradiation (output) such as the high voltage generation unit 122 is controlled.

  For example, the main control unit 121 generates an instruction signal for timing X-ray irradiation based on the X-ray irradiation instruction signal and irradiation time information included in the X-ray irradiation conditions. A voltage is supplied to the high voltage generator 122 by this instruction signal. Further, it receives fluoroscopic irradiation conditions (such as X-ray irradiation conditions) according to the comparison result of a pixel value comparison unit 154 described later. The main control unit 121 controls the high voltage generation unit 122 and the like based on the adjusted fluoroscopic irradiation condition.

  Further, when the operator performs an operation for interrupting fluoroscopic imaging by the operation unit 162, an X-ray irradiation stop instruction signal is sent from the arithmetic control unit 11 to the main control unit 121. In response to the signal, the main control unit 121 stops driving each unit related to X-ray irradiation (output) such as the high voltage generation unit 122 and stops X-ray irradiation.

  When the main control unit 121 receives an instruction signal to start partial fluoroscopy, the main control unit 121 receives the position information corresponding to the position information of the partial fluoroscopic region of interest R2 being received by the aperture control unit 13. Information on the partial fluoroscopic region of interest R2 is sent to the pixel value calculation unit 153.

<X-ray control unit 12-high voltage generation unit 122>
The main controller 121 controls the high voltage generator 122 to apply a high voltage necessary for X-ray irradiation to the X-ray tube 3. Application of the high voltage by the high voltage generator 122 can employ, for example, a high frequency inverter method. That is, the high voltage generator 122 rectifies the 50/60 Hz AC power source to obtain a direct current. Further, the high voltage generator 122 converts it into a high frequency alternating current of several kHz or more and boosts it. Further, the high voltage generator 122 rectifies and applies it again. In fluoroscopy, the X-ray control unit 12 repeatedly performs such an operation. Thereby, photographing is repeatedly performed.
That is, in the fluoroscopic control, the main control unit 121 performs control to irradiate the subject with pulsed X-rays at predetermined time intervals via the high voltage generation unit 122. A fluoroscopic image is generated by this fluoroscopy. Note that the fluoroscopic irradiation condition corresponds to an example of “operation condition of photographing unit”.

  In addition, the X-ray control unit 12 performs control related to X-ray irradiation in response to the adjusted fluoroscopic irradiation conditions according to the ABC control by the collected data processing unit 15. The specific control contents of the collected data processing unit 15 will be described later.

  Further, when the operator performs an operation for interrupting fluoroscopic imaging by the operation unit 162, an X-ray irradiation stop instruction signal is sent from the arithmetic control unit 11 to the main control unit 121. In response to the signal, the main control unit 121 stops driving each unit related to X-ray irradiation (output) such as the high voltage generation unit 122 and stops X-ray irradiation. Details of the ABC control in the X-ray control unit 12 will be described later.

<X-ray tube 3>
The X-ray tube 3 generates X-rays having a predetermined intensity in response to the application of the high voltage generated by the high voltage generator. The high voltage value or current value applied to the X-ray tube 3 can be set by the user using the user interface 16, or can be configured to be set automatically.

<X-ray diaphragm 4>
FIG. 2 is a schematic perspective view showing an example of the configuration of the X-ray diaphragm 4. For example, as shown in FIG. 2, the X-ray diaphragm 4 is configured by arranging plate-shaped diaphragm blades 41, 42, 43, 44 in four directions. The diaphragm blades 41 to 44 are made of a material that absorbs X-rays such as tungsten and molybdenum. Further, the diaphragm blades 41 to 44 are arranged so that their end surfaces are orthogonal to each other with respect to the end surfaces of adjacent blades, and the openings formed on the inner end surfaces of the diaphragm blades 41 to 44 are rectangular. Yes.

<Aperture control unit 13>
The diaphragm control unit 13 functions to form irradiation fields of various forms (sizes and shapes) by moving the diaphragm blades 41 to 44 of the X-ray diaphragm 4 respectively. The diaphragm control unit 13 is provided with an actuator that drives the diaphragm blades 41 to 44 and a control unit (such as a microprocessor) that controls the actuator. The diaphragm control unit 13 moves the diaphragm blades 41 and 42 in the lateral direction 2b of the bed 2 (direction orthogonal to the longitudinal direction 2a), respectively, and moves the diaphragm blades 43 and 44 in the longitudinal direction 2a of the bed 2 respectively. (See FIG. 2). The control of the X-ray diaphragm 4 by the diaphragm control unit 13 is performed based on the position information of the region of interest received from the fluoroscopic irradiation condition setting unit 18.

  As described above, the X-ray diaphragm 4 controlled by the diaphragm controller 13 causes the X-ray tube 3 to be the apex and the detection surface of the X-ray detector 5 to be the bottom surface. (See FIG. 1) is formed, and an X-ray irradiation field corresponding to the X-ray passage region F is formed.

  Here, the irradiation field means a common area of the X-ray passing area and a plane crossing the X-ray passing area, in other words, an area where the X-ray is irradiated to the plane. For example, the X-ray irradiation field on the subject P includes a longitudinal direction 2a and a short direction 2b, and a plane passing through the subject P is a target region. Further, the X-ray irradiation field on the detection surface of the X-ray detection unit 5 includes the longitudinal direction 2a and the short direction 2b, and a plane passing through the detection surface of the X-ray detection unit 5 is the X-ray irradiation target region. Become.

  If there is an instruction to shift to partial fluoroscopy while fluoroscopy is being performed, the diaphragm control unit 13 narrows the irradiation field. Alternatively, once the fluoroscopy is finished, when there is an instruction to limit the fluoroscopy and the irradiation field again, the aperture control unit 13 narrows the irradiation field. In the following, for the convenience of explanation, the fluoroscopic range is narrowed during fluoroscopy, and fluoroscopy (second imaging) performed in a region of interest that is narrower than the fluoroscopic range is simply referred to as “partial fluoroscopy”. Further, the region of interest in partial fluoroscopy is simply referred to as “regional region of interest for partial fluoroscopy”. A perspective image generated by partial perspective is simply referred to as “partial perspective image”. The fluoroscopic range corresponds to an example of “first X-ray irradiation range”. The partial fluoroscopic region of interest corresponds to an example of a “second X-ray irradiation range”.

  Here, with reference to FIG. 3, the partial fluoroscopy and the region of interest R2 for partial fluoroscopy will be described with reference to an example of performing fluoroscopy with ablation treatment. FIG. 3 is a schematic diagram illustrating an example of a relationship between a normal region of interest R1 and a partial perspective region of interest R2. In fluoroscopy in the case of ablation treatment, at the time before and after insertion of the catheter, for example, as shown in FIG. 3, the range including the insertion position of the catheter and the target site T (arrhythmia etc.) of the ablation treatment is a normal region of interest R1. May be set as

  Thereafter, when the catheter advances to the target site, the operator may instruct partial fluoroscopy and specify the partial fluoroscopic region of interest R2 via the operation unit 162. For example, the operator designates a region of interest R2 for partial fluoroscopy in a narrow range that includes a catheter approaching (or has reached) the target site and the target site and does not include the insertion position of the catheter. That is, the partial fluoroscopic region of interest overlaps at least the region of interest R1 (first fluoroscopic range or the like) in LIH (Last Image Hold) and is specified as a range narrower than the region of interest. Note that the LIH image is a still image showing the state (background) around the partial fluoroscopic region of interest, and is the last image (frame) in the fluoroscopy before partial fluoroscopy.

  Specifically, the operator uses the operation unit 162 to set a region of interest (imaging range) on the region of interest setting screen (for example, FIG. 3) displayed on the display unit 161 based on the subject (or the top). It is possible. For example, in this region-of-interest setting screen, it is assumed that the subject and the top plate are shown. On the screen, a frame display (R1, R2, etc.) indicating the region of interest is displayed with respect to the display of the subject, and this frame display is specified by enlarging or reducing the range by an operator's operation. Shall be able to. The operator can determine the region of interest by operating the operation unit 162 so that the insertion position of the catheter or the like and the lesioned part are included in the frame display. The region of interest determined here is sent to the fluoroscopic irradiation condition setting unit 18 and is set as an imaging range by the fluoroscopic irradiation condition setting unit 18.

  When the region of interest is set on the region-of-interest setting screen in this way, the fluoroscopic irradiation condition setting unit 18 captures, for example, the relative position of the region of interest with respect to the top board with reference to the coordinate position on the region-of-interest setting screen Set as range information. Information on the imaging range set here is sent from the fluoroscopic irradiation condition setting unit 18 to the aperture control unit 13 via the calculation control unit 11. In addition, when the touch-panel type user interface 16 is used, there is an input directly on the display unit 161, and the region of interest is set.

  When the partial fluoroscopic region of interest R2 is designated, the diaphragm control unit 13 moves the diaphragm blades 41 to 44 of the X-ray diaphragm 4 to limit the irradiation field to a range corresponding to the partial fluoroscopic region of interest R2. .

  Further, information on the imaging range such as the partial fluoroscopic region of interest R <b> 2 is also transmitted to the X-ray control unit 12. As described above, the information on the imaging range is used by the X-ray control unit 12 to calculate the statistical value of the brightness level of the fluoroscopic image.

<X-ray detection part 5>
The X-ray detection unit 5 detects X-rays transmitted through the subject, and converts the detection result (hereinafter referred to as “detection data”) into an electrical signal. Detection data is output to the collected data processing unit 15 by the X-ray detection unit 5. As the X-ray detection unit 5, a flat X-ray detection unit (Flat Panel Detector) or a combination of an image intensifier (II) and a TV camera can be used.

  The image intensifier converts X-rays to light on a phosphor screen such as a scintillator and emits photoelectrons from a photocathode made in contact with the phosphor screen. Further, the image intensifier focuses and accelerates the emitted photoelectrons with an electron lens made of a focus electrode and an anode, thereby forming an electron image on the output phosphor screen. Further, the image intensifier converts an electronic image into a visible image on the output phosphor screen and captures it with a TV camera. Image data (detection data) is obtained by this photographing.

  The planar X-ray detection unit has a detection surface configured by arranging multi-row, multi-column X-ray detection elements. A direct conversion type or the like can be used as the X-ray detection element. According to this X-ray detection element, electron-hole pairs in the semiconductor are generated by X-rays. Further, charge data is obtained by utilizing the movement to the electrode (ie, photoconductive phenomenon). Note that the charge data output from each element includes coordinate information of the element in a two-dimensional coordinate system based on a two-dimensional element array.

  As an example of the X-ray detection element of the planar X-ray detection unit, an indirect conversion type that converts transmitted X-rays into charge data using a phosphor, a photoelectric conversion element, or the like can be used. A planar X-ray detection unit having this X-ray detection element will be described with reference to FIG. FIG. 4 is a schematic block diagram illustrating an example of a functional configuration of the X-ray detection unit 5 according to the embodiment. As shown in FIG. 4, the X-ray detector 5 includes a flat detector 51, a gate driver 52, and a projection data generator 53. Among these, the projection data generation unit 53 includes a charge / voltage converter 531, an A / D converter 532, and a parallel / serial converter 533.

  The detection elements arranged two-dimensionally in the flat panel detector 51 receive X-rays that have passed through the subject P, and accumulate signal charges proportional to the amount of X-ray transmission. The gate driver 52 receives a clock pulse from the arithmetic control unit 11 when the X-ray irradiation is completed. When the gate driver 52 receives the clock pulse, the gate driver 52 supplies a driving pulse to a TFT (Thin Film Transistor / thin film transistor) of the flat panel detector 51 and sequentially reads out the accumulated signal charges.

  The read signal charge is sent to the charge / voltage converter 531 of the projection data generation unit 53. The charge / voltage converter 531 converts the signal charge into a voltage. Further, the voltage is converted into a digital signal by the A / D converter 532. Thereafter, the parallel / serial converter 533 converts the digital signal as detection data for one line. The parallel / serial converter 533 temporarily stores detection data for one line in the buffer memory. Then, the parallel / serial converter 533 serially reads the detection data stored in its own buffer memory in units of lines and sequentially stores it in the storage unit 156 of the collected data processing unit 15 to generate two-dimensional detection data. Note that the X-ray detector 5 shown in FIG. 4 is an example of the X-ray detector in this embodiment.

<Moving unit 6 / Drive control unit 14>
The moving unit 6 allows the X-ray tube 3, the X-ray diaphragm 4, and the X-ray detection unit 5 to move integrally. The moving unit 6 is driven by the drive control unit 14. The drive control unit 14 includes a drive mechanism that drives the moving unit 6 and a control unit (such as a microprocessor) that controls the operation of the drive mechanism. Hereinafter, the X-ray tube 3, the X-ray diaphragm 4, and the X-ray detection unit 5 may be collectively referred to as “X-ray imaging system”. This X-ray imaging system corresponds to an example of an “imaging unit”.

<Collecting data processing unit 15>
The collected data processing unit 15 performs various image processing and the like on the detection data to form an image (image data). The collected data processing unit 15 includes a computer that functions in this way. Details of the collected data processing unit 15 will be described later. The collected data processing unit 15 is an example of a function of an “X-ray image generation unit”.

Further, the collected data processing unit 15 performs the first ABC control and the second ABC control. The first ABC control corresponds to fluoroscopy in a normal region of interest (hereinafter, simply referred to as “first imaging”). The second ABC control corresponds to fluoroscopy in a region of interest that is narrower than the normal fluoroscopy range (hereinafter simply referred to as “second imaging”) (see FIG. 3 R1 and R2). In the first ABC control, for example, the collected data processing unit 15 receives information on the preset brightness threshold α ₁ from the fluoroscopic irradiation condition setting unit 18. The collected data processing unit 15 in the first ABC control, statistical value of the luminance (pixel value) in the current fluoroscopic image (mean, median, etc.) determine the beta _1. The collected data processing unit 15 further compares the threshold value α ₁ with the statistical value β ₁ . The collected data processing unit 15 reflects the result of the comparison in fluoroscopic irradiation conditions such as the X-ray conditions (tube voltage kV, tube current / irradiation time product mAs) in the X-ray control unit 12. Note that the fluoroscopic irradiation condition corresponds to an example of “operation condition of photographing unit”.

Also in the second ABC control, for example, the collected data processing unit 15 obtains the statistical value of the brightness of the fluoroscopic image. However, in the second ABC control, the collected data processing unit 15 narrows the range of the calculation target of the statistical value of luminance based on the information of the partial fluoroscopic region of interest R2 described later via the X-ray control unit 12. Focus on a range of interest. Hereinafter, the statistical value of the pixel value of each pixel in the narrow region of interest is described as “statistical value β ₂ ” in distinction from the statistical value β ₁ .

<Calculation control unit 11>
The arithmetic control unit 11 controls each unit of the X-ray diagnostic apparatus 100 (X-ray control unit 12, aperture control unit 13, drive control unit 14, collection data processing unit 15, user interface 16, fluoroscopic irradiation condition setting unit 18 and the like). In addition, various arithmetic processes are executed.

  The arithmetic control unit 11 includes, for example, a microprocessor such as a CPU (Central Processing Unit), a storage device (such as a memory or a hard disk drive) that stores a predetermined computer program and stores various data. The microprocessor executes control and arithmetic processing related to this embodiment by executing this computer program.

<Fluoroscopic irradiation condition setting unit 18>
The fluoroscopic irradiation condition setting unit 18 receives input from the operation unit 162 via the arithmetic control unit 11, and based on the input, fluoroscopic irradiation conditions such as X-ray conditions and region of interest (ROI) position information, and detection data Set the collection conditions. For example, in the setting of fluoroscopic irradiation conditions for fluoroscopy, when the operator sets the tube voltage kV according to the body thickness of the subject or the imaging region, the fluoroscopic irradiation condition setting unit 18 responds accordingly by the tube current / irradiation time product mAs. Set. The set fluoroscopic irradiation conditions and detection data collection conditions are sent to the X-ray control unit 12 and the aperture control unit 13 via the calculation control unit 11.

Further, the fluoroscopic irradiation condition setting unit 18 receives an input of the threshold value α ₁ used for the first ABC control and the second ABC control from the operation unit 162 via the calculation control unit 11. Fluoroscopy radiation condition setting unit 18 stores the threshold value alpha _1. When the first ABC control is performed by the collected data processing unit 15, the fluoroscopic irradiation condition setting unit 18 sends the input threshold value α ₁ to the collected data processing unit 15 via the calculation control unit 11. Input threshold alpha ₁ may be preset to fluoroscopic irradiation condition setting unit 18, or may be set in response to the execution of the shooting. This threshold α ₁ is a threshold for comparison with the statistical value β ₁ of the pixel value of the _first X-ray image and the statistical value β _{2 of} the second X-ray image, which is obtained by the pixel value calculation unit 153 described later. is there. Examples of the statistical value of the pixel value include an average value, an intermediate value, a standard deviation, a minimum value, and a maximum value of the pixel values. The threshold value is set according to the statistical value calculation method.

Further, the fluoroscopic irradiation condition setting unit 18 sends the input threshold value α ₁ to the collected data processing unit 15 when the collected data processing unit 15 performs the second ABC control. The collected data processing unit 15 executes the first ABC control and the second ABC control based on the threshold value α ₁ received from the fluoroscopic irradiation condition setting unit 18. Specific contents of ABC control will be described later. The fluoroscopic irradiation condition setting unit 18 functions as an example of a “first storage unit”.

  Further, the fluoroscopic irradiation condition setting unit 18 receives information on the normal region of interest R1 and the region of interest R2 for partial fluoroscopy from the operation unit 162 via the arithmetic control unit 11. For example, in the fluoroscopic irradiation condition setting screen as shown in FIG. 3, when the normal region of interest R <b> 1 and the partial fluoroscopic region of interest R <b> 2 are set by the operation of the operator, these are set from the operation unit 162 via the arithmetic control unit 11. Receive location information of the region of interest. This position information is set as an imaging range by the fluoroscopic irradiation condition setting unit 18.

(Configuration of the collected data processing unit 15)
Next, the configuration of the collected data processing unit 15 in the X-ray imaging apparatus will be described with reference to FIG. FIG. 5 is a schematic block diagram illustrating a part of the functional configuration of the collected data processing unit 15 according to the embodiment. The collected data processing unit 15 performs various image processing and the like on the detection data to form an image (image data). Further, the collected data processing unit 15 performs ABC control, and sends the fluoroscopic irradiation condition based on the processing result to the X-ray control unit 12.

  As shown in FIG. 5, the collected data processing unit 15 includes an interface 151, an image generation unit 152, a pixel value calculation unit 153, and a pixel value comparison unit 154.

<Interface 151>
As shown in FIG. 1, the collected data processing unit 15 is connected to the X-ray detection unit 5. The interface 151 receives detection data from the X-ray detection unit 5. Detection data received via the interface 151 is stored in the storage unit 156.

<Image Generation Unit 152>
The image generation unit 152 generates an X-ray image based on the detection data. For example, the image generation unit 152 generates two-dimensional image data based on the detection data. The image generation unit 152 may perform reconstruction based on two-dimensional detection data of a plurality of frames, generate volume data, and store the volume data in the storage unit 156. Further, when detection data is sequentially transmitted from the X-ray detection unit 5 by fluoroscopy, X-ray images are sequentially generated in response to receiving the detection data. Thereby, the image generation unit 152 generates a perspective image.

  Further, when the operator performs an operation of interrupting (stopping) the fluoroscopy with the operation unit 162 in a situation where fluoroscopy is performed by the X-ray imaging system, an X-ray irradiation stop instruction signal is sent to the X-ray control unit 12. . At this timing, an instruction to store the LIH image is sent from the arithmetic control unit 11 to the collected data processing unit 15. When receiving the storage instruction, the image generation unit 152 stores the LIH image in the storage unit 156 based on the fluoroscopic image. That is, when there is an instruction to interrupt fluoroscopy via the operation unit 162, the image generation unit 152 receives from the X-ray detection unit 5 and based on the last frame (detection data) in the fluoroscopic image stored in the storage unit 156. Separately from the perspective image displayed on the display unit 161, the generated image, that is, the LIH image is stored in the storage unit 156.

  However, the image generation unit 152 does not necessarily have to store the last frame of the fluoroscopic image in the storage unit 156. For example, when there is an image storage instruction from the operation unit 162 while fluoroscopy is being performed by the X-ray imaging system, the image generation unit 152 stores the generated X-ray image (here, a captured image / still image). 156 to store. In the following description, for the sake of convenience of explanation, both the image based on the last frame of the fluoroscopic image and the image based on the frame corresponding to the image storage instruction by the operator may be described as “LIH image”. . Such an LIH image corresponds to an example of a “first X-ray image”.

  The image generation unit 152 may generate a reduced image as a statistical value calculation target. The reduced image is generated for a different use from the display image, that is, an image for which a statistical value is obtained by the pixel value calculation unit 153. For example, when the display image is an image including “1024 * 1024” pixels, the reduced image generated by the image generation unit 152 can be image data “32 * 32” as an example. The reduced image may be a thumbnail or may be compressed image data. An example of the compression method is a method of frequency-decomposing and quantizing the display image data generated by the image generation unit 152.

<Outline of ABC Control of Collected Data Processing Unit 15>
Next, an outline of the collected data processing unit 15 will be described, and the configuration of the collected data processing unit 15 and the flow of ABC control performed by the collected data processing unit 15 will be described with reference to FIGS. 7 and 8. FIG. 7 is a schematic flowchart illustrating a flow of first ABC control of the medical image diagnostic apparatus that performs fluoroscopy. The collected data processing unit 15 corresponds to an example of an “adjustment unit”. The collected data processing unit 15 corresponds to an example of a “control unit” together with the X-ray control unit 12.

As the first ABC control and the second ABC control, the collected data processing unit 15 adjusts the fluoroscopic irradiation condition and changes the luminance value based on the pixel value of the fluoroscopic image. That collection data processing section 15 obtains statistics beta ₁ of the pixel values (luminance values) for each pixel in the fluoroscopic image, also obtains statistics beta ₂ of the pixel values for each pixel in the partial fluoroscopic image (pixel value calculation unit 153). The collected data processing unit 15 also receives information on the threshold value α ₁ of the pixel value of the fluoroscopic image stored in the fluoroscopic irradiation condition setting unit 18. The collected data processing unit 15 compares the threshold value α ₁ with the statistical value β ₁ . The collected data processing unit 15 compares the statistical values beta ₂ threshold alpha ₁ and the partial fluoroscopic image (pixel value comparison unit 154). As a result of the comparison, when the statistical value β ₁ does not correspond to the threshold value α ₁ , or when the statistical value β ₂ does not correspond to the threshold value α ₁ , the collected data processing unit 15 changes the fluoroscopic irradiation condition. For example, if the luminance value of the fluoroscopic image is lower than the threshold value, control for increasing the fluoroscopic irradiation condition is performed.

<Pixel value calculation unit 153>
Pixel value calculating unit 153 calculates the statistic value beta ₁ of the pixel values in the X-ray image such as fluoroscopic images taken in the normal region of interest R1. Further, the pixel value calculation unit 153 calculates the statistic value beta ₂ of the pixel values of the captured partial perspective image in the partial fluoroscopic ROI R2. The statistical value β ₁ and the statistical value β ₂ are, for example, an average value, an intermediate value, a standard deviation, a minimum value, and a maximum value of pixel values. The pixel value calculation unit 153 receives the X-ray image data generated by the image generation unit 152 via the calculation control unit 11. As a specific example, the pixel value calculation unit 153 obtains an average value of pixel values in a perspective image or an average value of pixel values in a partial perspective image. The pixel value calculation unit 153 sends information on the obtained statistical values β ₁ and β ₂ to the pixel value comparison unit 154. In fluoroscopy, the pixel value calculation unit 153 repeats this process. Note that the target for obtaining the statistical value β by the pixel value calculation unit 153 may be the reduced image.

<Pixel value comparison unit 154>
Pixel value comparison unit 154, the calculation control unit 11 receives the threshold value alpha ₁ for information of the pixel values from the perspective irradiation condition setting unit 18 through the interface 151 or the like. Further, the pixel value comparison unit 154 receives information on the statistical value β ₁ or the statistical value β ₂ of the pixel value obtained by the pixel value calculation unit 153 and compares it with the threshold value α ₁ . Further, the fluoroscopic irradiation conditions are adjusted based on the comparison result. As an example of the adjustment, when “β = 200” with respect to “α = 300”, the ratio “300/200” is reflected in the conditions set in advance by the fluoroscopic irradiation condition setting unit 18.

The pixel value comparison unit 154 may be configured to send the comparison result to the main control unit 121. In this case, first, the pixel value comparison unit 154 sends the obtained comparison result to the main control unit 121. The main control unit 121 adjusts the fluoroscopic irradiation conditions based on the comparison result, similarly to the processing of the pixel value comparison unit 154. The comparison result here may be, for example, information indicating a difference between the threshold value α and the statistical value β ₁ or the statistical value β ₂ of the pixel value, or may be information indicating a ratio. .

Further, the pixel value comparison unit 154 may determine whether the comparison result is within a predetermined range. That is, the pixel value comparison unit 154 determines whether the difference or ratio between the threshold value α ₁ and the statistical value β ₁ of the pixel value obtained by the pixel value calculation unit 153 is within a predetermined range. In addition, the pixel value comparison unit 154 determines whether the difference or ratio between the threshold value α ₁ and the pixel value statistical value β ₂ obtained by the pixel value calculation unit 153 is within a predetermined range. This is because the pixel value comparison unit 154 determines whether the pixel value (luminance) of the fluoroscopic image or the partial fluoroscopic image is within a preset range. In this example, if the difference is within a predetermined range, the pixel value comparison unit 154 determines that the change of the X-ray condition is unnecessary, and does not send the comparison result to the main control unit 121. If the difference is outside the predetermined range, the comparison result, that is, the difference is sent to the main control unit 121. The main control unit 121 adjusts the X-ray condition according to this difference.

  The main control unit 121 is not limited to the configuration in which the comparison result is received from the pixel value comparison unit 154 and the X-ray irradiation condition is adjusted, but the pixel value comparison unit 154 adjusts the X-ray irradiation condition based on the comparison result. May be. In this example, the pixel value comparison unit 154 sends the adjusted X-ray irradiation conditions to the main control unit 121. The main control unit 121 performs control related to X-ray irradiation based on the adjusted X-ray irradiation conditions received from the pixel value comparison unit 154.

<Storage unit 156>
The storage unit 156 stores the two-dimensional detection data received via the interface 151 as described above. In addition, the storage unit 156 stores each X-ray image used for a composite image such as a LIH image or an angiographic image. The storage unit 156 stores volume data. The detection data and the X-ray image may be continuously stored in the storage unit 156 every time they are generated, and may be arbitrarily read according to the operation of the operator. The detection data and the X-ray image may be temporarily stored in the storage unit 156. The stored data may be a moving image or a still image.

<Operation>
Next, the operation of the X-ray control unit 12 in the first ABC control will be described with reference to FIG. 6 with an example of fluoroscopy in the normal region of interest R1.

(S01)
The main control unit 121 in the X-ray control unit 12 receives a preset fluoroscopic irradiation condition (X-ray condition or the like) from the fluoroscopic irradiation condition setting unit 18. Further, when the operator gives an instruction to start fluoroscopy in the normal region of interest R <b> 1 by the operation unit 162, an X-ray irradiation instruction signal is sent to the main control unit 121 via the arithmetic control unit 11.

(S02)
The main control unit 121 controls the high voltage generating unit 122 and the like based on the fluoroscopic irradiation conditions received from the fluoroscopic irradiation condition setting unit 18 and applies a voltage to the X-ray tube 3. Further, the diaphragm control unit 13 moves the X-ray diaphragm 4 based on the position information of the normal region of interest R1 received from the fluoroscopic irradiation condition setting unit 18 to form an irradiation field. As a result of these operations, X-rays are emitted.

(S03)
When the X-ray detection unit 5 generates detection data based on transmitted X-rays, the detection data is sent to the collected data processing unit 15. When the collected data processing unit 15 receives the detection data via the interface 151, the collected data processing unit 15 temporarily stores it in the storage unit 156. The image generation unit 152 reads detection data from the storage unit 156. Further, the image generation unit 152 generates a fluoroscopic image and causes the display unit 161 to display the fluoroscopic image. At this time, the image generation unit 152 may generate a reduced image.

(S04)
The collected data processing unit 15 receives perspective image data from the image generation unit 152. Alternatively, the collected data processing unit 15 reads the fluoroscopic image data from the storage unit 156. The pixel value calculation unit 153 obtains a statistical value β ₁ (average value or the like) of the pixel value in the fluoroscopic image acquired from the image generation unit 152 or the storage unit 156. Or the pixel value comparison unit 154 obtains statistics beta ₁ of the pixel values of the reduced image.

(S05)
The pixel value comparison unit 154 compares the statistical value β ₁ of the pixel value obtained by the pixel value calculation unit 153 with the threshold value α ₁ received from the fluoroscopic irradiation condition setting unit 18. The pixel value comparison unit 154 (or the main control unit 121) refers to the comparison result by the pixel value comparison unit 154 and determines whether to change fluoroscopic irradiation conditions such as an X-ray condition. The pixel value comparison unit 154 may determine whether the comparison result is within a predetermined range.

(S06)
Results of the comparison by the pixel value comparison unit 154, the larger the difference between the statistical value beta ₁ and the threshold alpha ₁ pixel value (S05; Yes), the pixel value comparison unit 154 (or the main control unit 121) is tube voltage kV, Adjust (change) parameters related to tube current / irradiation time product mAs.

(S07)
Further, if the difference between the pixel value statistical value β ₁ and the threshold value α ₁ is small (S05; No), the pixel value comparison unit 154 (or the main control unit 121) keeps the fluoroscopic irradiation condition as it is. maintain.

(S08)
The pixel value comparison unit 154 (or the main control unit 121) determines whether to continue fluoroscopy. For example, when the operator gives an instruction to stop fluoroscopy via the operation unit 162, an X-ray irradiation stop instruction signal is sent to the main control unit 121 via the arithmetic control unit 11. The main control unit 121 sequentially repeats the operations of S02 to S07 until receiving the X-ray irradiation stop instruction signal. Note that the process of S08 has been described as a subsequent process of S06 or S07 for convenience of explanation, but when the main control unit 121 receives an X-ray irradiation stop instruction signal at any time of S02 to S05, at that time. The main control unit 121 stops the X-ray irradiation.

  Further, in one example, when an operation of stopping X-ray irradiation (stopping fluoroscopy) is performed, the main control unit 121 stops driving of each unit related to X-ray irradiation (output) such as the high voltage generation unit 122 and X-rays Stop irradiation. Further, the image generation unit 152 stores the LIH image in the storage unit 156 in response to the operation of the stop instruction. Further, the main control unit 121 stores the fluoroscopic irradiation conditions corresponding to the LIH image in a storage unit (not shown).

(Configuration of the display data processing unit 17)
Next, the configuration of the display data processing unit 17 in the X-ray imaging apparatus will be described with reference to FIG. FIG. 7 is a schematic block diagram illustrating a part of the functional configuration of the display data processing unit 17 according to the embodiment. The display data processing unit 17 performs various types of image processing on the image data generated by the collected data processing unit 15 to form an image. As shown in FIG. 7, the display data processing unit 17 includes an interface 171, a subtraction processing unit 172, an image adjustment unit 173, and an image composition unit 174.

<Interface 171>
As shown in FIG. 7, the display data processing unit 17 is connected to the calculation control unit 11. The interface 171 receives image data of an X-ray image from the collected data processing unit 15 via the arithmetic control unit 11. The image data received via the interface 171 is temporarily stored in the storage unit 156.

<Subtraction processing unit 172>
When generating a difference image, the subtraction processing unit 172 receives image data having different properties and performs these subtraction processes. For example, the subtraction processing unit 172 may include a non-contrast X-ray image (hereinafter referred to as “mask image”) and an X-ray image after contrast (hereinafter referred to as “contrast image”). The subtraction process is performed. As a result, an angiographic (DSA (Digital Subtraction Angiography)) image is generated.

  As another example, the subtraction processing unit 172 performs subtraction processing between an X-ray image obtained by high energy X-rays and an X-ray image obtained by low energy. Thereby, an energy subtraction image is generated. The subtraction processing unit 172 sends the image data (digital angiographic image, energy subtraction image, etc.) subjected to the subtraction processing to the image adjustment unit 173 or the image composition unit 174. The subtraction processing unit 172 may not be provided depending on the configuration of the X-ray imaging apparatus.

<Image adjustment unit 173>
The image adjustment unit 173 receives image data from the collected data processing unit 15 or the storage unit 156 and performs image processing. The image adjustment unit 173 performs image processing such as image sharpening, noise reduction, S / N ratio improvement, edge detection, and contour enhancement. The image adjustment unit 173 has functions such as a so-called spatial filter, spatial frequency filter, and temporal filter. Examples of the spatial filter and the spatial frequency filter include a filter that performs smoothing processing and a filter that performs edge detection. For example, as a filter that performs the smoothing process, a moving average filter, a weighted average filter, a Gaussian filter, a median filter, and the like can be given.

  The image adjustment unit 173 includes an arbitrary filter such as a Sobel filter (Sobel Filter), a Prewitt filter, a Roberts filter (Roberts Filter), a Laplacian filter (Laplacian filter) that performs edge detection. The image adjustment unit 173 may have functions such as an image addition process and a recursive filter as a so-called time filter. The image adjustment unit 173 may have functions such as a low-pass filter, a high-pass filter, a band-pass filter, a band elimination filter, and an all-pass filter.

  The image adjustment unit 173 performs the above filtering (high frequency emphasis, etc.) and affine transformation (image enlargement, movement, etc.) on the image data. For example, when the image generation unit 152 generates a digital angiographic image, the image adjustment unit 173 performs these processes on the projection data. Further, the image adjustment unit 173 may emphasize the high frequency component using an unsharp mask.

  Further, the image adjustment unit 173 may read the volume data from the storage unit 156 after the image generation unit 152 generates the volume data, and perform volume rendering processing based on the volume data. By this volume rendering process, for example, a road map image or the like referred to in interventional treatment is generated.

<Image composition unit 174>
The image combining unit 174 combines (pastes) a plurality of X-ray image data according to the image to be displayed, and generates combined X-ray image data. Hereinafter, the synthesized X-ray image data may be simply referred to as “synthesized image”. The image synthesis unit 174 synthesizes, for example, an LIH image and a partial perspective image described later. As another example, the image combining unit 174 combines a road map image and a perspective image based on volume data.

  When the composite image of the LIH image and the partial fluoroscopic image is generated by the image combining unit 174, alignment is performed based on information on the designation operation of the partial fluoroscopic region of interest R2, and the combined image is combined. That is, the partial fluoroscopic region of interest R2 is set so as to at least overlap with the region of interest R1 (such as the first fluoroscopic range) in the LIH image, and the position of the partial fluoroscopic region of interest R2 is indicated by the coordinates in the LIH image. Is possible. Therefore, the image composition unit 174 receives the stored position information of the partial fluoroscopic region of interest R2, and composes the partial fluoroscopic image so as to be bonded to the LIH image based on the position information and the coordinates of the LIH image. .

  Further, when the composite image of the LIH image and the partial perspective image is generated by the image composition unit 174, the composition ratio of each image can be arbitrarily set, but at least to the extent that the partial perspective image can be recognized in the composite image. A composition ratio of the partial perspective images is set.

(Partial perspective)
Next, the flow of the control of the X-ray control unit 12 and the processing of the collected data processing unit 15 relating to partial fluoroscopy in the first embodiment will be described with reference to FIG. FIG. 8 is a schematic flowchart for explaining a flow of second ABC control of the medical image diagnostic apparatus for performing partial fluoroscopy in the first embodiment. As described above, when the operator performs an operation of interrupting the fluoroscopy with the operation unit 162 in a situation where fluoroscopy is performed in the normal region of interest R1 by the X-ray imaging system, the X-ray control unit 12 is irradiated with X-rays. A stop instruction signal is sent. Further, when the operator performs an operation of starting partial fluoroscopy and specifying a region of interest for partial fluoroscopy R2 using the operation unit 162, the X-ray control unit 12 performs control in partial fluoroscopy.

(S11)
When the operator performs an operation to start partial fluoroscopy and designates a partial fluoroscopic region of interest R2 by using the operation unit 162, positional information of one partial fluoroscopic region of interest R2 is sent to the aperture control unit 13 and the pixel value calculation unit 153. It is done. In addition, an instruction to start the other partial fluoroscopy is sent to the main control unit 121.

(S12)
The diaphragm control unit 13 moves the diaphragm blades 41 to 44 of the X-ray diaphragm 4 based on the position information of the partial fluoroscopic region of interest R2 so that the X-ray irradiation field is in a range corresponding to the partial fluoroscopic region of interest R2. limit. The fluoroscopic irradiation condition setting unit 18 sends the fluoroscopic irradiation conditions to the main control unit 121.

(S13)
When the diaphragm control unit 13 narrows the X-ray irradiation field based on the position information of the partial fluoroscopic region of interest R2, the position information of the partial fluoroscopic region of interest R2 is obtained from the fluoroscopic irradiation condition setting unit 18 as a pixel value. It is sent to the calculation unit 153. The pixel value calculation unit 153 changes a range that is a calculation target of the statistical value of the pixel value of the partial fluoroscopic image to be generated according to the partial fluoroscopic region of interest R2.

(S14)
Based on the fluoroscopic irradiation condition received from the fluoroscopic irradiation condition setting unit 18, the X-ray control unit 12 controls the high voltage generation unit 122 and the like, and X-rays are irradiated in the partial fluoroscopic region of interest R2.

(S15)
When the X-ray detection unit 5 generates detection data based on transmitted X-rays, the detection data is sent to the collected data processing unit 15. When the collected data processing unit 15 receives the detection data via the interface 151, the collected data processing unit 15 temporarily stores it in the storage unit 156. The image generation unit 152 reads the detection data from the storage unit 156 and generates a partial perspective image.

(S16)
The pixel value calculation unit 153 obtains a statistical value β ₂ (average value or the like) of the pixel value in the partial perspective image received from the image generation unit 152. The pixel value comparison unit 154 compares the pixel value statistical value β ₂ obtained by the pixel value calculation unit 153 with the threshold value α ₁ received from the fluoroscopic irradiation condition setting unit 18. The pixel value comparison unit 154 may determine whether the comparison result is within a predetermined range.

(S17)
The pixel value comparison unit 154 (or the main control unit 121) refers to the comparison result by the pixel value comparison unit 154 and determines whether the difference (or ratio) between the statistical value β ₂ of the pixel value and the threshold value α ₁ is large. To determine whether to change the fluoroscopic irradiation conditions such as the X-ray conditions.

(S18)
Greater the difference between the statistical value beta ₂ and the threshold alpha ₁ pixel value (or ratio) of (S17; Yes), the main control unit 121 to change the parameters relating to the tube voltage kV, tube current, irradiation time product mAs.

(S19)
If the difference (or ratio) between the pixel value statistical value β ₂ and the threshold value α ₁ is small (S17; No), the main control unit 121 maintains the fluoroscopic irradiation condition as it is.

(S20)
The main control unit 121 determines whether to continue the partial fluoroscopy. For example, when the operator gives an instruction to stop partial fluoroscopy via the operation unit 162, an X-ray irradiation stop instruction signal is sent to the main control unit 121 via the arithmetic control unit 11. The main control unit 121 sequentially repeats the operations of S14 to S19 until receiving the X-ray irradiation stop instruction signal. The process of S20 has been described as a subsequent process of S18 or S19 for convenience of explanation. However, if the main control unit 121 receives an X-ray irradiation stop instruction signal at any time of S14 to S17, at that time. The main control unit 121 stops the X-ray irradiation.

  Further, in one example, when an X-ray irradiation stop instruction signal (fluoroscopy stop) is operated, the main control unit 121 stops driving each unit related to X-ray irradiation (output) such as the high voltage generation unit 122. , X-ray irradiation is stopped.

  Note that after step S15 (generation of a partial perspective image), the image composition unit 174 receives the partial perspective image generated by the image generation unit 152 and further reads out the LIH image. Further, the image synthesis unit 174 synthesizes the partial perspective image with the read LIH image. The composite image is displayed on the display unit 161.

(Function and effect)
The operation and effect of the medical image diagnostic apparatus according to the present embodiment described above will be described.

  When the fluoroscopy (first imaging) in the normal region of interest R1 is stopped and the fluoroscopy in the partial fluoroscopy region of interest R2 is started, the medical image diagnostic apparatus in the present embodiment starts from the first ABC control to the second. Switch to ABC control. That is, when partial fluoroscopy is started, the statistical value calculation range of the pixel values of the partial fluoroscopic image is made to correspond to the partial fluoroscopic region of interest R2. Therefore, it is possible to avoid a situation in which the statistical value becomes too low due to the calculation range of the statistical value to be subjected to ABC control exceeding the range of the partial fluoroscopic image. As a result, it is possible to prevent an increase in the exposure dose of the subject due to the X-ray condition being increased by the second ABC control in partial fluoroscopy.

  In addition, the medical image diagnostic apparatus according to the present embodiment is not limited to the case of partial fluoroscopy, and the calculation range of the statistical value of the pixel value corresponds to the fluoroscopy range even when the region of interest is unintentionally narrowed. Limit the area of interest. Therefore, it is possible to prevent an increase in the exposure dose of the subject due to unintentionally increasing the X-ray condition.

[First modification]
Next, a first modification of the medical image diagnostic apparatus according to the first embodiment will be described. In the medical image diagnostic apparatus according to the first embodiment, the first ABC control and the second ABC control are performed based on the luminance of the X-ray image generated by the image generation unit 152. However, the present invention is not limited to this, and these ABC controls may be performed based on the detection data.

[Second modification]
In the medical image diagnostic apparatus according to the first embodiment, the collected data processing unit 15 is configured to compare a statistical value of a pixel value with a threshold value. However, it is not limited to this configuration. For example, the collected data processing unit 15 may be configured to compare each pixel in the fluoroscopic image or the partial fluoroscopic image with a threshold value, and further compare the average value of the comparison result with the threshold value. In this example, a first threshold value for comparison with each pixel and a second threshold value for comparison with the average value may be set respectively.

  The same effects as those of the above-described embodiment can also be realized by the configurations of the X-ray imaging apparatuses according to the first and second modifications described above.

[Third Modification]
In the medical image diagnostic apparatus according to the first embodiment, the comparison result of the pixel value comparison unit 154 or the fluoroscopic irradiation condition adjusted based on the comparison result is also sent to the main control unit 121 in the control of partial fluoroscopy. However, the parameters of the adjusted fluoroscopic irradiation conditions may be further adjusted. For example, the X-ray control unit 12 in this modification stores a predetermined coefficient in a storage unit (not shown). In this case, when adjusting the fluoroscopic irradiation condition based on the comparison result after switching to partial fluoroscopy, the main control unit 121 reads a predetermined coefficient from the storage unit. Further, the main control unit 121 reflects the predetermined coefficient read in the adjusted fluoroscopic irradiation condition and uses it as a control parameter for the high voltage generation unit 122.

  As this predetermined coefficient, a coefficient that reduces the dose of X-rays irradiated in partial fluoroscopy is set. As an example of this modification, the comparison result received from the pixel value comparison unit 154 is a ratio between the threshold value α and the statistical value β, and this ratio is multiplied by the fluoroscopic irradiation condition. In this configuration, the value of the predetermined coefficient is “0.65”, for example. In this case, a value obtained by multiplying the ratio by “0.65” is reflected in the fluoroscopic irradiation condition. Even if the comparison result obtained by the pixel value comparison unit 154 in partial fluoroscopy is reflected in the fluoroscopic irradiation conditions, as in this example, by further multiplying the fluoroscopic irradiation conditions by a coefficient that reduces the X-ray dose, Control is performed so that the X-ray irradiation dose becomes 1 or less.

  As described above, in partial fluoroscopy, there is a decrease in scattered radiation due to a narrowed irradiation range, which may reduce the brightness of the image. in this case. If ABC control for adjusting the fluoroscopic irradiation conditions is performed, it may be difficult to suppress the exposure amount of the subject. In this regard, under the configuration and control as in the present modification, it is possible to reduce the exposure amount.

[Second Embodiment]
Next, a medical image diagnostic apparatus according to the second embodiment will be described with reference to FIGS. FIG. 9 is a schematic block diagram illustrating a part of the functional configuration of the collected data processing unit 15 according to the second embodiment. FIG. 10 is a schematic flowchart illustrating the flow of the first gain adjustment of the medical image diagnostic apparatus according to the second embodiment that performs fluoroscopy. In the second embodiment, the contents of the collected data processing unit 15 and the X-ray control unit 12 are different from those of the first embodiment. Other parts are the same as those of the medical image diagnostic apparatus according to the first embodiment. Hereinafter, the difference from the first embodiment will be mainly described.

<First gain adjusting unit 155>
As illustrated in FIG. 9, the collected data processing unit 15 according to the second embodiment includes a first gain adjustment unit 155 in addition to the interface 151, the image generation unit 152, the pixel value calculation unit 153, and the pixel value comparison unit 154. It consists of The first gain adjustment unit 155 performs adjustment of the pixel value of the image data, that is, gain adjustment, after the image generation unit 152 generates image data (raw image data) based on the detection data. For example, the first gain adjustment unit 155 receives the image data from the image generation unit 152, or reads the image data from the storage unit 156, and performs gain adjustment of pixel values in the image data. The tone (brightness) of the X-ray image is adjusted by the gain adjustment in the first gain adjustment unit 155. Note that the raw image data is image data generated by the image generation unit 152 and is not subjected to the predetermined image processing and image synthesis described in the first embodiment.

  The first gain adjustment unit 155 may have a first lookup table as an example. The first look-up table has a contrast table format that corrects (outputs) pixel values (input) of image data to predetermined pixel values set in advance. In this case, the first gain adjustment unit 155 performs gain adjustment using the first lookup table. That is, the pixel value (gradation) of each pixel in the image data received from the storage unit 156 is corrected to an arbitrary pixel value using the first lookup table.

In addition, the first look-up table in the first gain adjustment unit 155 is adjusted based on the comparison result of the pixel value comparison unit 154 in the setting value. That is, similarly to the first embodiment, the pixel value calculation unit 153 performs statistical analysis of pixel values of X-ray image data (or a reduced image thereof) such as a perspective image generated by the image generation unit 152 in normal perspective and partial perspective. The value β ₁ (or β ₂ ) is calculated. Further, the pixel value comparison unit 154 receives data of the threshold value α ₁ from the fluoroscopic irradiation condition setting unit 18 via the calculation control unit 11. The pixel value comparison unit 154 compares the threshold value α ₁ with the statistical value β ₁ (or β ₂ ). In the second embodiment, the comparison results (difference / ratio, etc.) obtained here are used not only for adjustment of fluoroscopic irradiation conditions but also for gain adjustment of image data.

That is, the first gain adjustment unit 155 receives the comparison result from the pixel value comparison unit 154, and adjusts the setting value of the first lookup table based on the result. For example, with respect to the threshold value alpha _1, when the value of the statistic beta _{1 (or} beta ₂₎ is low, it changes the set value of the first look-up table so that the pixel values of the image data approaches the threshold alpha _1. When the gain adjustment of the image data (raw image data) is performed using the first look-up table after the change, for example, the pixel value (luminance) of a normal perspective image or a partial perspective image is increased, and the visibility of the perspective image or the partial perspective image is increased. It is possible to improve.

  Note that the threshold value α may be set based on a statistical value of pixel values of the LIH image. That is, if the luminance of the entire LIH image and the luminance of the partial perspective image are greatly different, the visibility of the composite image may be hindered. However, if the threshold α is set according to the statistical value of the pixel value of the LIH image, the LIH This is because the luminance of the image can be made to correspond to the luminance of the partial perspective image.

  Note that the pixel value comparison unit 154 may determine whether the comparison result is within a predetermined range. In this example, if the difference is within a predetermined range, the pixel value comparison unit 154 determines that the first gain adjustment unit 155 does not need to change the setting value of the first lookup table, and the first gain adjustment unit 155. Do not send comparison results to. If the difference is outside the predetermined range, the comparison result (difference or the like) is sent to the first gain adjustment unit 155. The first gain adjustment unit 155 changes the set value of the first lookup table in accordance with the result of this comparison, and adjusts the pixel value of image data such as a fluoroscopic image.

  The first gain adjustment unit 155 is not limited to the configuration in which the setting value of the first look-up table is changed in response to the comparison result from the pixel value comparison unit 154, but the pixel value comparison unit 154 may change the first value based on the comparison result. The set value of one lookup table may be changed. In this example, the pixel value comparison unit 154 sends the changed setting value of the first lookup table to the first gain adjustment unit 155. The first gain adjustment unit 155 performs gain adjustment of the image data (raw image data) based on the changed first lookup table received from the pixel value comparison unit 154.

<Operation>
Next, the flow of gain adjustment by the first gain adjustment unit 155 will be described with reference to the flowchart of FIG. FIG. 10 relates to an example of fluoroscopy in the normal region of interest R1. In FIG. 10, the flow of ABC control for adjusting the fluoroscopic irradiation conditions is omitted.

(S21-S24)
Also in the ABC control related to the first gain adjustment of the second embodiment, the processes from the start of fluoroscopy (S21, S22) to the generation of a fluoroscopic image (S23) are the same as S01 to S03 of the first embodiment. Therefore, explanation of these processes is omitted. Further, the calculation of the statistical value beta ₁ (or beta _2), since the even compare (S24) the threshold value alpha ₁ and the statistic beta ₁ (or beta _2), is similar to S04 in the first embodiment, the description Omit.

(S25)
The pixel value comparison unit 154 (or the main control unit 121) refers to the comparison result by the pixel value comparison unit 154 and determines whether to change the first look-up table (first LUT) in the first gain adjustment unit 155.

(S26)
If the difference (absolute value or the like) between the statistical value β ₁ (or β ₂ ) of the pixel value and the threshold value α ₁ is larger than a predetermined value (S25; Yes), the pixel value comparison unit 154 (or the main control unit 121) The information indicating the difference or the information indicating the ratio is sent to the first gain adjustment unit 155. The first gain adjustment unit 155 receives the information and adjusts (changes) the setting value of the first lookup table. The first gain adjustment unit 155 adjusts the gain of the image data generated by the image generation unit 152 according to the adjusted first look-up table. Note that the adjustment of the first lookup table may be performed by the pixel value comparison unit 154 based on the comparison result.

(S27)
Further, the pixel value comparison unit 154 (or the main control unit 121), if the difference or ratio between the statistical value β ₁ (or β ₂ ) of the pixel value and the threshold value α ₁ is small (S25; No), the first lookup table. Keep the original.

(S28)
The determination of continuation of fluoroscopy by the pixel value comparison unit 154 (or the main control unit 121) is the same as the processing of S08 in the first embodiment, and thus description thereof is omitted.

  Further, in one example, when an operation of stopping X-ray irradiation (stopping fluoroscopy) is performed, the main control unit 121 stops driving of each unit related to X-ray irradiation (output) such as the high voltage generation unit 122 and X-rays Stop irradiation. Further, the image generation unit 152 stores the LIH image in the storage unit 156 according to the operation of the stop instruction.

In the second embodiment, even after the X-ray irradiation control by the X-ray control unit 12 is switched to partial fluoroscopy, the pixel value calculation unit 153 performs the partial fluoroscopic image generated by the image generation unit 152 (or a reduced image thereof). ) Statistical value β ₂ is obtained. Similarly, the pixel value comparison unit 154 compares the statistical value β ₂ and the threshold value α ₁ even in partial perspective. Therefore, in the second embodiment, the comparison result of the pixel value comparison unit 154 is used for adjustment of the fluoroscopic irradiation condition and adjustment of the setting value of the first lookup table in the first gain adjustment unit 155.

(Function and effect)
The operation and effect of the medical image diagnostic apparatus according to the second embodiment described above will be described.

  When the fluoroscopy (first imaging) in the normal region of interest R1 is stopped and the fluoroscopy in the partial fluoroscopy region of interest R2 is started, the medical image diagnostic apparatus in the present embodiment starts from the first ABC control to the second. Switch to ABC control. That is, when partial fluoroscopy is started, the statistical value calculation range of the pixel values of the partial fluoroscopic image is made to correspond to the partial fluoroscopic region of interest R2. Therefore, it is possible to avoid a situation in which the statistical value becomes too low due to the calculation range of the statistical value to be subjected to ABC control exceeding the range of the partial fluoroscopic image. As a result, it is possible to prevent an increase in the exposure dose of the subject due to the X-ray condition being increased by the second ABC control in partial fluoroscopy.

  Further, when the statistic values of the pixel values of the LIH image and the statistic values of the pixel values of the partial perspective image are different, there is a possibility that the visibility may be hindered when the brightness of each image is different. However, in the second embodiment, the gain adjustment of the image data generated by the image generation unit 152 is adjusted according to the brightness of the fluoroscopic image or the partial fluoroscopic image. Therefore, the brightness of the LIH image and the brightness of the partial perspective image are made to correspond to each other, and a situation in which the visibility is lowered can be avoided.

  In addition, since the first gain adjustment unit 155 performs gain adjustment before image processing by the image adjustment unit 173, the image adjustment unit 173 performs image processing with the pixel values of the image data adjusted. . That is, the medical image diagnostic apparatus according to the second embodiment can effectively perform the image processing.

[Third Embodiment]
Next, a medical image diagnostic apparatus according to a third embodiment will be described with reference to FIGS. FIG. 11 is a schematic block diagram illustrating a part of the functional configuration of the display data processing unit 17 according to the third embodiment. In the third embodiment, the contents of the collected data processing unit 15 and the X-ray control unit 12 are different from those of the first embodiment. Other parts are the same as those of the medical image diagnostic apparatus according to the first embodiment. Hereinafter, the difference from the first embodiment will be mainly described.

<Second gain adjustment unit 175>
As shown in FIG. 11, the display data processing unit 17 according to the third embodiment includes a second gain adjustment unit 175 in addition to the interface 171, the subtraction processing unit 172, the image adjustment unit 173, and the image composition unit 174. Has been. The second gain adjustment unit 175 adjusts the gain of the image data for display, which is generated by the image generation unit 152 and is subjected to the predetermined image processing and image synthesis described in the first embodiment. That is, the pixel value of the image data is adjusted. The display image data includes, for example, a digital angiographic image, an energy subtraction image, a 3D road map image, and the like.

  For example, the image data generated by the collected data processing unit 15 is subjected to subtraction processing by the subtraction processing unit 172 and becomes a subtraction image. The image data from the collected data processing unit 15 is subjected to predetermined image processing by the image adjustment unit 173. The image data received from the collected data processing unit 15 is combined with other image data by the image combining unit 174. The second gain adjustment unit 175 of the third embodiment performs gain adjustment on these image data.

  Further, the image data generated by the collected data processing unit 15 may be stored in the storage unit 156. The second gain adjustment unit 175 can also adjust the gain of the pixel value in the image data read from the storage unit 156 by the operator when the fluoroscopy is interrupted or completed. As described above, the tone (brightness) of the X-ray image is adjusted by the gain adjustment in the second gain adjustment unit 175.

  The second gain adjustment unit 175 has a second lookup table. The second gain adjustment unit 175 performs gain adjustment using the second lookup table. That is, the second gain adjustment unit 175 corrects the pixel value (gradation) of each pixel in the X-ray image generated by the image generation unit 152 to a pixel value arbitrarily set by the second lookup table. In other words, the second look-up table adjusts the window level (WL / Window Level) and window width (WW / Window Width) in the generated X-ray image, performs window conversion, and converts the pixel value of the X-ray image ( (Luminance value / Tint value) is adjusted.

In the third embodiment, the setting value of the second lookup table is adjusted according to the comparison result between the pixel value of the X-ray image and the threshold, such as the perspective image and the partial perspective image generated by the image generation unit 152. That is, similarly to the first embodiment, the pixel value calculation unit 153 obtains the statistical value β ₁ (or β ₂ ) of the pixel value in the X-ray image and sends it to the pixel value comparison unit 154. Further pixel value comparison unit 154 receives the threshold value alpha ₁ for information of the pixel values. The pixel value comparison unit 154 compares the statistical value β ₁ (or β ₂ ) of the pixel value with the threshold value α ₁ . The pixel value comparison unit 154 according to the third embodiment sends the comparison result to the second gain adjustment unit 175.

  Note that the pixel value comparison unit 154 may determine whether the comparison result is within a predetermined range. In this example, if the difference is within a predetermined range, the pixel value comparison unit 154 determines that the second gain adjustment unit 175 does not need to change the second lookup table, and the second gain adjustment unit 175 performs comparison. Do not send results. If the difference is outside the predetermined range, the comparison result (difference, etc.) is sent to the second gain adjustment unit 175. The second gain adjustment unit 175 adjusts the setting value of the second lookup table according to the result of this comparison, and adjusts the pixel value of the X-ray image.

  The second gain adjustment unit 175 is not limited to the configuration in which the second lookup table is changed by receiving the comparison result from the pixel value comparison unit 154, but the pixel value comparison unit 154 performs the second lookup based on the comparison result. You may change the table. In this example, the pixel value comparison unit 154 sends the changed second lookup table to the second gain adjustment unit 175. The second gain adjustment unit 175 performs window conversion of an X-ray image such as a perspective image based on the changed second lookup table received from the pixel value comparison unit 154.

  Further, the set value of the second lookup table can be adjusted by the operation unit 162 or the like. Since the user can adjust the setting value of the second lookup table by an operation, the gain adjustment of the pixel value (luminance) of the X-ray image by the second gain adjustment unit 175 can be arbitrarily performed. Therefore, even an X-ray image once stored can be read and adjusted to an arbitrary luminance.

<Operation>
Next, the flow of gain adjustment related to the second gain adjustment unit 175 described above will be described with reference to the flowchart of FIG. FIG. 12 relates to an example of fluoroscopy in the normal region of interest R1. Moreover, in FIG. 12, the flow of ABC control regarding adjustment of fluoroscopic irradiation conditions is omitted.

(S31-S34)
Also in the ABC control related to the second gain adjustment of the third embodiment, the processes from the start of fluoroscopy (S31, S32) to the generation of a fluoroscopic image (S33) are the same as S01 to S03 of the first embodiment. Therefore, explanation of these processes is omitted. Further, the calculation of the statistical value beta _1, since the even comparator threshold alpha ₁ and the statistic beta ₁ (S34), is similar to S04 in the first embodiment, description thereof will be omitted.

(S35)
Whether the pixel value comparison unit 154 (or the main control unit 121) refers to the comparison result by the pixel value comparison unit 154 and changes the setting value of the second lookup table (second LUT) in the second gain adjustment unit 175. to decide.

(S36)
If the difference between the statistical value beta ₁ and the threshold alpha ₁ pixel values (absolute value) is greater than a predetermined value (S35; Yes), the pixel value comparison unit 154 (or the main control unit 121), the second gain adjustment Information indicating the difference or information indicating the ratio is sent to the unit 175. The second gain adjustment unit 175 receives the information and adjusts (changes) the setting value of the second lookup table. The second gain adjustment unit 175 adjusts the gain of the image data that has undergone image processing and the like, according to the adjusted second look-up table. The adjustment of the second lookup table may be performed by the pixel value comparison unit 154 based on the comparison result.

(S37)
The pixel value comparison unit 154 (or the main control unit 121), when the difference or the ratio between the statistical value beta ₁ and the threshold alpha ₁ pixel value is small (S35; No), second look to the second gain adjusting unit 175 Do not send instructions to adjust the uptable. However, the second gain adjustment unit 175 determines whether there is an instruction for the window conversion operation from the operation unit 162.

(S38)
If there is no instruction for adjusting the second lookup table from either the pixel value comparison unit 154 or the operation unit 162 (S35; No ； S37; No), the second gain adjustment unit 175 is based on the second lookup table. Keep it.

(S39)
The determination of continuation of fluoroscopy by the pixel value comparison unit 154 (or the main control unit 121) is the same as the processing of S08 in the first embodiment, and thus description thereof is omitted.

  Further, in one example, when an operation of stopping X-ray irradiation (stopping fluoroscopy) is performed, the main control unit 121 stops driving of each unit related to X-ray irradiation (output) such as the high voltage generation unit 122 and X-rays Stop irradiation. Further, the image generation unit 152 stores the LIH image in the storage unit 156 according to the operation of the stop instruction. Further, the main control unit 121 stores the fluoroscopic irradiation conditions corresponding to the LIH image in a storage unit (not shown).

In the third embodiment, even after the control related to X-ray irradiation by the X-ray control unit 12 is switched to partial fluoroscopy, the pixel value calculation unit 153 performs the partial fluoroscopic image generated by the image generation unit 152 (or a reduced size thereof). Image) statistical value β ₁ (or β ₂ ) is obtained. Similarly, the pixel value comparison unit 154 compares the statistical value β ₁ (or β ₂ ) with the threshold value α ₁ even in partial perspective. However, in the third embodiment, the comparison result of the pixel value comparison unit 154 is not used for adjustment of the fluoroscopic condition, but is used for adjustment of the setting value of the second lookup table in the second gain adjustment unit 175.

(Other examples)
Moreover, the structure which calculates | requires ratio of threshold value (alpha) ₁ and statistical value (beta) ₁ (or (beta) ₂ ) of the pixel value of a partial perspective image may be sufficient. For example, setting the threshold value alpha ₁ as an adjustment value of the look-up table of the gain adjustment in partial perspective. In this configuration, the second gain adjustment unit 175 obtains a ratio between the threshold α ₁ and the statistical value β ₁ (or β ₂ ) of the pixel value of the partial perspective image, and changes the second lookup table based on the obtained ratio. May be.

(Function and effect)
The operation and effect of the medical image diagnostic apparatus according to the third embodiment described above will be described.

  In the medical image diagnostic apparatus according to the present embodiment, when the fluoroscopy (first imaging) in the normal region of interest R1 is stopped and the fluoroscopy in the region of partial fluoroscopy R2 is started, the statistical value of the pixel value of the partial fluoroscopic image Is made to correspond to the partial fluoroscopic region of interest R2. Therefore, it is possible to avoid a situation in which the statistical value is too low due to the statistical value calculation range exceeding the partial fluoroscopic image range.

  In addition, the medical image diagnostic apparatus according to the present embodiment is not limited to the case of partial fluoroscopy, and the calculation range of the statistical value of the pixel value corresponds to the fluoroscopy range even when the region of interest is unintentionally narrowed. Limit the area of interest.

  Further, when the statistic values of the pixel values of the LIH image and the statistic values of the pixel values of the partial perspective image are different from each other, there is a risk that the visibility may be hindered. However, in the third embodiment, the window conversion of the partial perspective image generated by the image generation unit 152 is adjusted according to the luminance of the partial perspective image. Therefore, the brightness of the LIH image and the brightness of the partial perspective image are made to correspond to each other, and a situation in which the visibility is lowered can be avoided.

[Fourth Embodiment]
Next, a medical image diagnostic apparatus according to the fourth embodiment will be described. In the fourth embodiment, data for gain adjustment is different from that in the second embodiment. Other parts are the same as those of the medical image diagnostic apparatus according to the second embodiment. Hereinafter, the difference from the second embodiment will be mainly described.

  Similar to the second embodiment, in the fourth embodiment, the pixel value comparison unit 154 compares the statistical value with the threshold value. In the fourth embodiment, the calculation target of the statistical value is normal fluoroscopy or partial fluoroscopy. This is the pixel value (signal value) of the detection data (digital signal) at. The gain adjustment is performed by a third gain adjustment unit (not shown). The pixel value comparison unit 154 or the third gain adjustment unit changes the third lookup table in accordance with the comparison result between the statistical value obtained by the pixel value calculation unit 153 and the threshold value. This configuration is the difference between the fourth embodiment and the second embodiment. The other points are the same.

(Function and effect)
The operation and effect of the medical image diagnostic apparatus according to the fourth embodiment described above will be described.

  When the fluoroscopy (first imaging) in the normal region of interest R1 is stopped and the fluoroscopy in the partial fluoroscopy region of interest R2 is started, the medical image diagnostic apparatus in the present embodiment starts from the first ABC control to the second. Switch to ABC control. That is, when partial fluoroscopy is started, the statistical value calculation range of the pixel values of the partial fluoroscopic image is made to correspond to the partial fluoroscopic region of interest R2. Therefore, it is possible to avoid a situation in which the statistical value becomes too low due to the calculation range of the statistical value to be subjected to ABC control exceeding the range of the partial fluoroscopic image. As a result, it is possible to prevent an increase in the exposure dose of the subject due to the X-ray condition being increased by the second ABC control in partial fluoroscopy.

  In addition, the medical image diagnostic apparatus according to the present embodiment is not limited to the case of partial fluoroscopy, and the calculation range of the statistical value of the pixel value corresponds to the fluoroscopy range even when the region of interest is unintentionally narrowed. Limit the area of interest. Therefore, it is possible to prevent an increase in the exposure dose of the subject due to unintentionally increasing the X-ray condition.

  Further, when the statistic values of the pixel values of the LIH image and the statistic values of the pixel values of the partial perspective image are different, there is a possibility that the visibility may be hindered when the brightness of each image is different. However, in the fifth embodiment, the gain adjustment of the detection data (digital signal) stored in the receiving storage unit 156 from the X-ray detection unit 5 is adjusted according to the brightness of the fluoroscopic image or the partial fluoroscopic image. Therefore, the brightness of the LIH image and the brightness of the partial perspective image are made to correspond to each other, and a situation in which the visibility is lowered can be avoided. In addition, since the third gain adjustment unit may perform gain adjustment before image processing by the image adjustment unit 173, the image adjustment unit 173 performs image processing in a state where the pixel value of the partial fluoroscopic detection data is adjusted. Will do. That is, the medical image diagnostic apparatus according to the fourth embodiment may be able to perform the image processing effectively.

[Fifth Embodiment]
Next, a medical image diagnostic apparatus according to the fifth embodiment will be described with reference to FIGS. In the fifth embodiment, the setting contents of the fluoroscopic irradiation conditions for the fluoroscopic irradiation condition setting unit 18 and the processing contents of the collection data processing unit 15 and the X-ray control unit 12 are different from those of the first embodiment. Other parts are the same as those of the medical image diagnostic apparatus according to the first embodiment. Hereinafter, the difference from the first embodiment will be mainly described.

(Overview)
The medical image diagnostic apparatus according to the fifth embodiment excludes pixels having a predetermined pixel value, for example, pixels having a pixel value less than a threshold value, when calculating the statistical value β ₂ of the pixel value of the partial fluoroscopic image. Thus, to calculate the statistical value of the statistical value β pixels tend to lower the calculated value of _2, for example, the pixel value of the partially transparent image except the pixels showing the prosthetic valve and pacemakers. Calculating a statistical value beta ₂ of the pixel values with the exception of the portions that tend to lower the luminance in the partial fluoroscopic image other words, a second ABC control.

(Collecting data processing unit 15)
The collected data processing unit 15 sends the fluoroscopic image generated by the image generation unit 152 to the pixel value calculation unit 153 in the first ABC control as in the first embodiment. Further, the collected data processing unit 15 in the fifth embodiment sends the partial fluoroscopic image generated by the image generation unit 152 to the pixel value comparison unit 154 in the second ABC control.

(Fluoroscopic irradiation condition setting unit 18)
Similarly to the first embodiment, the fluoroscopic irradiation condition setting unit 18 receives an input of the threshold value α ₁ to be compared with the statistical value β ₁ or the statistical value β ₂ from the operation unit 162 via the calculation control unit 11. Fluoroscopy radiation condition setting unit 18 stores the threshold value alpha _1. In the fifth embodiment, similarly to the threshold value α ₁ , the input of the threshold value α ₂ is received and stored. Pixel value calculating unit 153 in the fifth embodiment performs threshold processing for each pixel in the partial perspective image based on a threshold alpha _2. By the threshold processing, the pixel value calculation unit 153 identifies a pixel having a predetermined pixel value in the set statistical value calculation range. Statistics beta ₂ of obtaining the pixel value of the partial fluoroscopic image by the pixel value calculation unit 153 is as follows.

(Pixel value comparison unit 154)
In the second ABC control, the pixel value comparison unit 154 receives partial perspective image data from the image generation unit 152. When the pixel value comparison unit 154 receives the partial fluoroscopic image, the pixel value comparison unit 154 receives information on the threshold value α ₂ from the fluoroscopic irradiation condition setting unit 18. Further pixel value comparison unit 154 compares the pixel value of each pixel in the partial fluoroscopic image with the threshold alpha _2. Further, the pixel value comparison unit 154 identifies, for example, a pixel having a pixel value less than the threshold value α ₂ (or less than or equal to the threshold value α ₂ ) among the pixels. Further, the pixel value comparison unit 154 sends the partial perspective image data to the pixel value calculation unit 153 together with the position information of the specified pixel.

(Pixel value calculation unit 153)
The pixel value calculation unit 153 obtains the statistical value β ₁ as in the first embodiment. In addition, the pixel value calculation unit 153 in the fifth embodiment receives partial perspective image data not from the image generation unit 152 but from the pixel value comparison unit 154. The pixel value calculation unit 153 receives the position information of the pixel specified by the pixel value comparison unit 154 together with the partial perspective image data from the pixel value comparison unit 154.

The pixel value calculation unit 153 excludes pixels having pixel values less than the threshold value α ₂ (or less than the threshold value α ₂ ) based on the position information received from the pixel value comparison unit 154 among the pixels of the partial perspective image. The statistical value β ₂ is obtained. In other words, the pixel value calculation unit 153 specifies a pixel other than a pixel having a pixel value less than the threshold value α ₂ (or less than or equal to the threshold value α ₂ ) and obtains the statistical value β ₂ . The pixel value calculation unit 153 sends the statistical value β ₂ thus obtained to the pixel value comparison unit 154. Similar to the first embodiment, the pixel value comparison unit 154 compares the statistical value β ₂ and the threshold value α ₁ and sends the comparison result to the X-ray control unit 12.

(Other examples)
The pixel value calculation unit 153 is not limited to the configuration except for pixels identified by the pixel value comparison section 154 as described above obtains statistics beta _2. For example, the pixel value calculation unit 153, based on the position information of a particular pixel received from pixel value comparison section 154, statistics beta ₂ by replacing the threshold alpha ₂ than the pixel value to the threshold value alpha ₂ or more pixel values You may ask for it. The threshold value alpha ₂ or more pixel values, for example, the average value of the pixel values of all pixels of the partial fluoroscopic image, an intermediate value, minimum value, maximum value, etc. is applicable. Further, adjacent to a particular pixel may be replaced with a pixel having a threshold alpha ₂ or more pixel values.

In addition, the pixel value comparison unit 154 is not limited to a configuration that specifies a pixel having a pixel value less than the threshold α ₂ (or less than or equal to the threshold α ₂ ), and may specify a pixel having a pixel value within a predetermined range. . That is, an upper limit and a lower limit of pixel values that are subject to statistical value calculation by the pixel value calculation unit 153 may be set.

(Partial perspective)
Next, with reference to FIGS. 13 and 14, the flow of the control of the X-ray control unit 12 and the processing of the collected data processing unit 15 regarding partial fluoroscopy in the fifth embodiment will be described. FIG. 13 and FIG. 14 are schematic flowcharts for explaining the flow of second ABC control of the medical image diagnostic apparatus regarding partial fluoroscopy in the fifth embodiment.

(S41)
Position information of the partial fluoroscopic region of interest R2 is sent to the aperture controller 13 and the pixel value calculator 153, and an instruction to start partial fluoroscopy is sent to the main controller 121.

(S42)
The aperture control unit 13 limits the X-ray irradiation field to a range corresponding to the partial fluoroscopic region of interest R2 based on the position information of the partial fluoroscopic region of interest R2. The fluoroscopic irradiation condition setting unit 18 sends the fluoroscopic irradiation conditions to the main control unit 121.

(S43)
The position information of the partial fluoroscopic region of interest R2 is sent from the fluoroscopic irradiation condition setting unit 18 to the pixel value calculation unit 153 in response to the aperture control unit 13 narrowing the X-ray irradiation field. The pixel value calculation unit 153 changes the range for which the statistical value is calculated to the partial fluoroscopic region of interest R2.

(S44)
Based on the fluoroscopic irradiation condition received from the fluoroscopic irradiation condition setting unit 18, the X-ray control unit 12 controls the high voltage generation unit 122 and the like, and X-rays are irradiated in the partial fluoroscopic region of interest R2.

(S45)
When the X-ray detection unit 5 generates detection data based on transmitted X-rays, the detection data is sent to the collected data processing unit 15. The collected data processing unit 15 temporarily stores the detection data in the storage unit 156. The image generation unit 152 reads detection data from the storage unit 156. Furthermore, the image generation unit 152 generates a partial perspective image.

(S46)
Pixel value comparison unit 154 compares the pixel value of each pixel in the partial fluoroscopic image with the threshold alpha _2. In one example, the pixel value comparison unit 154 identifies a pixel having a pixel value less than the threshold value α ₂ (or the threshold value α ₂ or less) among the pixels. Further, the pixel value comparison unit 154 sends the partial perspective image data to the pixel value calculation unit 153 together with the position information of the specified pixel. That is, here the pixel other than the pixel specified by the pixel value comparison section 154, and calculates target statistics beta _2.

(S47)
In one example, the pixel value calculation unit 153 obtains the statistical value β ₂ by excluding pixels having pixel values less than the threshold value α ₂ (or less than or equal to the threshold value α ₂ ).

(S48)
The pixel value comparison unit 154 compares the pixel value statistical value β ₂ obtained by the pixel value calculation unit 153 with the threshold value α ₁ received from the fluoroscopic irradiation condition setting unit 18. The pixel value comparison unit 154 may determine whether the comparison result is within a predetermined range.

(S49)
The pixel value comparison unit 154 (or the main control unit 121) refers to the comparison result by the pixel value comparison unit 154 and determines whether the difference (or ratio) between the statistical value β ₂ of the pixel value and the threshold value α ₁ is large. To determine whether to change the fluoroscopic irradiation conditions such as the X-ray conditions.

(S50)
Greater the difference between the statistical value beta ₂ and the threshold alpha ₁ pixel value (or ratio) of (S49; Yes), the main control unit 121 to change the parameters relating to the tube voltage kV, tube current, irradiation time product mAs.

(S51)
Further, if the difference (or ratio) between the pixel value statistical value β ₂ and the threshold value α ₁ is small (S49; No), the main control unit 121 maintains the fluoroscopic irradiation condition as it is.

(S52)
The main control unit 121 determines whether to continue the partial fluoroscopy. For example, when the operator gives an instruction to stop partial fluoroscopy via the operation unit 162, an X-ray irradiation stop instruction signal is sent to the main control unit 121 via the arithmetic control unit 11. The main control unit 121 sequentially repeats the operations of S44 to S51 until receiving the X-ray irradiation stop instruction signal. The process of S52 has been described as a subsequent process of S50 or S51 for convenience of explanation. However, when the main control unit 121 receives an X-ray irradiation stop instruction signal at any time point of S44 to S49, at that time point. The main control unit 121 stops the X-ray irradiation.

(Function and effect)
The operation and effect of the medical image diagnostic apparatus according to the fifth embodiment described above will be described.

  When the fluoroscopy in the normal region of interest R1 is stopped and the fluoroscopy in the partial fluoroscopy region of interest R2 is started, the medical image diagnostic apparatus according to the present embodiment switches from the first ABC control to the second ABC control. That is, when partial fluoroscopy is started, the statistical value calculation range of the pixel values of the partial fluoroscopic image is made to correspond to the partial fluoroscopic region of interest R2. Therefore, it is possible to avoid a situation in which the statistical value becomes too low due to the calculation range of the statistical value to be subjected to ABC control exceeding the range of the partial fluoroscopic image. As a result, it is possible to prevent an increase in the exposure dose of the subject due to the X-ray condition being increased by the second ABC control in partial fluoroscopy.

  In addition, the medical image diagnostic apparatus according to the present embodiment is not limited to the case of partial fluoroscopy, and the calculation range of the statistical value of the pixel value corresponds to the fluoroscopy range even when the region of interest is unintentionally narrowed. Limit the area of interest. Therefore, it is possible to prevent an increase in the exposure dose of the subject due to unintentionally increasing the X-ray condition.

The pixels in the partial fluoroscopic image include not only pixels within the range of the partial fluoroscopic region of interest R2, but also pixels within the range of the normal region of interest R1 and outside the range of the partial fluoroscopic region of interest R2 (such as a portion corresponding to a diaphragm blade). It may be. In addition, the partial fluoroscopic region of interest R2 may include a pixel group that indicates a structure such as a pacemaker or a bone that tends to have low luminance. In this regard, the medical image diagnostic apparatus according to the fifth embodiment, when calculating the statistical value β ₂ of the pixel value of the partial fluoroscopic image, excludes the statistical value β except for the pixels that tend to lower the calculated value of the statistical value β _{2. 2} is calculated. As a result, the X-ray condition is enhanced by the second ABC control in partial fluoroscopy, and it is possible to prevent an increase in the exposure dose of the subject.

[Sixth Embodiment]
Next, a medical image diagnostic apparatus according to the sixth embodiment will be described with reference to FIGS. FIG. 15 is a schematic block diagram illustrating a part of the functional configuration of the collected data processing unit 15 according to the sixth embodiment. In the sixth embodiment, the collected data processing unit 15 and the X-ray control unit 12 are different from those in the first and fifth embodiments. Other parts are the same as those of the medical image diagnostic apparatus according to the first and fifth embodiments. Hereinafter, the difference from the fifth embodiment will be mainly described.

(Overview)
The medical image diagnostic apparatus in the sixth embodiment, in calculating the statistical value beta ₂ of the pixel values of the partial fluoroscopic image, performs pattern recognition of each portion shown in partial perspective image. For example, the medical image diagnostic apparatus, the pattern of each structure which tends to lower the calculated value of the statistical value beta ₂ in a subject is registered more. The collected data processing unit 15 extracts a pixel group corresponding to the structure in the partial perspective image from the partial perspective image, and compares the extraction result with the registered pattern. The collected data processing unit 15 removes the structure correlated with the registered pattern from the partial perspective image and sends the structure to the pixel value calculation unit 153. Thus, to calculate the statistical value of the pixel values of the partially transparent image except to the extent (pixel group) which tends to lower the calculated value of the statistical value beta _2. Calculating a statistical value beta ₂ of the pixel values with the exception of the portions that tend to lower the luminance in the partial fluoroscopic image other words, a second ABC control.

(Storage unit 156)
The storage unit 156 in the collected data processing unit 15 is a subject such as an artificial valve, a pacemaker, an artificial object placed in the subject such as a coil, an insert such as a catheter or a guide wire, or a bone that exists for each imaging region. A plurality of patterns of structures such as internal tissues are stored. These patterns may be a three-dimensional shape of the structure, or may be a two-dimensional shape based on a plurality of detection angles in the structure. These patterns may be stored for each category according to the shape characteristics. Any of the structures indicated by the patterns stored in the storage unit 156 may have a high X-ray absorptance and a tendency for luminance to decrease in an image. Hereinafter, the pattern stored in the storage unit 156 may be referred to as a “specific structure pattern”.

(Comparator 159)
As shown in FIG. 15, the collected data processing unit 15 includes an interface 151, an image generation unit 152, an image calculation unit 153, a pixel value comparison unit 154, a first gain adjustment unit 155, and a comparison unit 159. .

  The comparison unit 159 receives image data of a partial perspective image generated by the image generation unit 152. The comparison unit 159 extracts each pixel group shown in the partial perspective image. The comparison unit 159 may extract each pixel group from the image data adjusted by the image adjustment unit 173. For example, the collected data processing unit 15 sends image data different from the partial fluoroscopic image to be a composite image to the image adjusting unit 173. The image adjustment unit 173 performs processing such as noise reduction, edge detection, and contour enhancement. The comparison unit 159 extracts the outline of each pixel group shown in the processed partial perspective image. Since this partial perspective image is different from the display mode on the display unit 161, it is possible to enhance the contour extraction without considering the visibility of the image.

  The comparison unit 159 extracts each pixel group whose contour is emphasized. The comparison unit 159 reads the stored specific structure pattern from the storage unit 156. Further, the comparison unit 159 compares the extracted pixel group with the specific structure pattern and determines whether or not there is a correlation. As an example, the comparison unit 159 first extracts feature points of the pixel group extracted from the partial perspective image. The feature point of the structure is a feature point in the contour shape of the structure. This feature point is collated with the read specific structure pattern.

  As another example, the comparison unit 159 may collate whether the outline of each pixel group in the partial perspective image correlates with the specific structure pattern.

  In any case, if the specific structure pattern stored in the storage unit 156 is three-dimensional, the comparison unit 159 identifies each pixel group (two-dimensional image) of the partial perspective image three-dimensionally. Matching is performed for each detection angle and detection direction with respect to the structure pattern.

  As a result of the collation, the comparison unit 159 obtains a degree of similarity, a degree of correlation, a matching rate, and the like between each pixel group in the partial perspective image and the specific structure pattern. As a result of the pattern recognition, if the similarity between the specific structure pattern and the pixel group is equal to or greater than a preset value, the comparison unit 159 determines that the pixel group in the partial perspective image is a structure ( For example, a pacemaker).

  When the comparison unit 159 determines that the pixel group indicated by the partial perspective image corresponds to the specific structure pattern stored in advance, the comparison unit 159 specifies pixels in a range occupied by the pixel group of the partial perspective image. Further, the comparison unit 159 excludes the specified range of pixels from the entire partial fluoroscopic image, and sends the partial fluoroscopic image data to the pixel value calculation unit 153.

(Pixel value calculation unit 153)
The pixel value calculation unit 153 obtains the statistical value β ₁ as in the first embodiment. Also, the pixel value calculation unit 153 in the sixth embodiment receives partial perspective image data from which pixels in the predetermined range are excluded from the comparison unit 159 in the collected data processing unit 15. Pixel value calculating unit 153, the data of the partial fluoroscopic image obtaining statistics beta ₂ as described above.

(Other examples)
The pixel value calculation unit 153 is not limited to the configuration for obtaining the statistical values beta ₂ parts fluoroscopic image pixels in a predetermined range are removed by the comparing unit 159 as described above. For example, the pixel value calculation unit 153 may perform a process of excluding pixels in a predetermined range. That is, when the comparison unit 159 determines that the pixel group indicated by the partial perspective image corresponds to the specific structure pattern stored in advance, the position information of the range occupied by the pixel group of the partial perspective image (coordinates in the partial perspective image, etc.) ). Further, the comparison unit 159 sends the specified positional information and the partial perspective image data from the entire partial perspective image to the pixel value calculation unit 153. Pixel value calculating unit 153 in this configuration, based on the received position information to exclude pixels in a predetermined range finding statistics beta _2.

Further, the pixel value calculation unit 153 is not limited to the configuration with the exception of the specified pixel as described above obtains statistics beta _2. For example, the pixel value calculation unit 153 obtains the statistical value β ₂ by replacing the pixel value of the specific pixel with the pixel value of another adjacent pixel based on the position information of the specific pixel received from the comparison unit 159. Also good.

(Partial perspective)
Next, with reference to FIG. 16 and FIG. 17, the flow of the process of the control of the X-ray control part 12 regarding the partial fluoroscopy and the acquisition data process part 15 in 6th Embodiment is demonstrated. 16 and 17 are schematic flowcharts for explaining the flow of second ABC control of the medical image diagnostic apparatus relating to partial fluoroscopy in the sixth embodiment.

(S61)
Position information of the partial fluoroscopic region of interest R2 is sent to the aperture controller 13 and the pixel value calculator 153, and an instruction to start partial fluoroscopy is sent to the main controller 121.

(S62)
The aperture control unit 13 limits the X-ray irradiation field to a range corresponding to the partial fluoroscopic region of interest R2 based on the position information of the partial fluoroscopic region of interest R2. The fluoroscopic irradiation condition setting unit 18 sends the fluoroscopic irradiation conditions to the main control unit 121.

(S63)
The position information of the partial fluoroscopic region of interest R2 is sent from the fluoroscopic irradiation condition setting unit 18 to the pixel value calculation unit 153 in response to the aperture control unit 13 narrowing the X-ray irradiation field. The pixel value calculation unit 153 changes the range for which the statistical value is calculated to the partial fluoroscopic region of interest R2.

(S64)
Based on the fluoroscopic irradiation condition received from the fluoroscopic irradiation condition setting unit 18, the X-ray control unit 12 controls the high voltage generation unit 122 and the like, and X-rays are irradiated in the partial fluoroscopic region of interest R2.

(S65)
When the X-ray detection unit 5 generates detection data based on transmitted X-rays, the detection data is sent to the collected data processing unit 15. The collected data processing unit 15 temporarily stores the detection data in the storage unit 156. The image generation unit 152 reads detection data from the storage unit 156. Furthermore, the image generation unit 152 generates a partial perspective image.

(S66)
In one example, the comparison unit 159 extracts a pixel group from the partial perspective image.

(S67)
As an example, the comparison unit 159 extracts the feature points of the pixel group extracted from the partial perspective image. The feature point of the structure is a feature point in the contour shape of the structure. This feature point is collated with the read specific structure pattern.

(S68)
As a result of the collation, the comparison unit 159 determines whether the similarity between each pixel group in the partial perspective image and the specific structure pattern is equal to or greater than a preset value. If the similarity or the like is equal to or greater than a set value, the pixel group in the partial perspective image is determined as a structure (for example, a pacemaker) related to the specific structure pattern.

(S69)
As an example, when the comparison unit 159 determines that the pixel group indicated by the partial perspective image corresponds to the specific structure pattern stored in advance (S68; Yes), the comparison unit 159 identifies pixels in a range occupied by the pixel group of the partial perspective image. To do. Further, the comparison unit 159 excludes the specified range of pixels from the entire partial fluoroscopic image, and sends the partial fluoroscopic image data to the pixel value calculation unit 153.

(S70)
The comparison unit 159 excludes the specified range of pixels from the entire partial fluoroscopic image, and sends the partial fluoroscopic image data to the pixel value calculation unit 153. When the comparison unit 159 determines that all of the pixel groups indicated by the partial perspective image do not correspond to the specific structure pattern stored in advance (S68; No), the image data of the partial perspective image is sent to the pixel value calculation unit 153 as it is. . Pixel value calculating unit 153 calculates the statistic value beta ₂ of the pixel values of the pixels in any of the above partial perspective image.

(S71)
The pixel value comparison unit 154 compares the pixel value statistical value β ₂ obtained by the pixel value calculation unit 153 with the threshold value α ₁ received from the fluoroscopic irradiation condition setting unit 18. The pixel value comparison unit 154 may determine whether the comparison result is within a predetermined range.

(S72)
The pixel value comparison unit 154 (or the main control unit 121) refers to the comparison result by the pixel value comparison unit 154 and determines whether the difference (or ratio) between the statistical value β ₂ of the pixel value and the threshold value α ₁ is large. To determine whether to change the fluoroscopic irradiation conditions such as the X-ray conditions.

(S73)
Greater the difference between the statistical value beta ₂ and the threshold alpha ₁ pixel value (or ratio) of (S72; Yes), the main control unit 121 to change the parameters relating to the tube voltage kV, tube current, irradiation time product mAs.

(S74)
The main control unit 121, the smaller the difference (or ratio) between the statistics beta ₂ and the threshold alpha ₁ pixel value (S72; No), the main control unit 121 maintains intact the fluoroscopic irradiation conditions.

(S75)
The main control unit 121 determines whether to continue the partial fluoroscopy. For example, when the operator gives an instruction to stop partial fluoroscopy via the operation unit 162, an X-ray irradiation stop instruction signal is sent to the main control unit 121 via the arithmetic control unit 11. The collected data processing unit 15 and the main control unit 121 sequentially repeat the operations of S64 to S74 until receiving the X-ray irradiation stop instruction signal. The process of S75 has been described as a subsequent process of S73 or S74 for convenience of explanation. However, if the main control unit 121 receives an X-ray irradiation stop instruction signal at any time point of S64 to S72, at that time point. The main control unit 121 stops the X-ray irradiation.

(Function and effect)
The operation and effect of the medical image diagnostic apparatus according to the sixth embodiment described above will be described.

  In the medical image diagnostic apparatus according to the present embodiment, when the fluoroscopy in the normal region of interest R1 is stopped and the fluoroscopy in the region of partial fluoroscopy R2 is started, the first ABC control is switched to the second ABC control. . That is, when partial fluoroscopy is started, the statistical value calculation range of the pixel values of the partial fluoroscopic image is made to correspond to the partial fluoroscopic region of interest R2. Therefore, it is possible to avoid a situation in which the statistical value becomes too low due to the calculation range of the statistical value to be subjected to ABC control exceeding the range of the partial fluoroscopic image. As a result, it is possible to prevent an increase in the exposure dose of the subject due to the X-ray condition being increased by the second ABC control in partial fluoroscopy.

  In addition, the medical image diagnostic apparatus according to the present embodiment is not limited to the case of partial fluoroscopy, and the calculation range of the statistical value of the pixel value corresponds to the fluoroscopy range even when the region of interest is unintentionally narrowed. Limit the area of interest. Therefore, it is possible to prevent an increase in the exposure dose of the subject due to unintentionally increasing the X-ray condition.

The pixels in the partial perspective image may include not only pixels within the range of the partial perspective region of interest R2 but also pixels within the range of the normal region of interest R1 and outside the range of the partial perspective region of interest R2. In addition, the partial fluoroscopic region of interest R2 may include a pixel group that indicates a structure such as a pacemaker or a bone that tends to have low luminance. In this regard, when calculating the statistical value β ₂ of the partial fluoroscopic image pixel value, the medical image diagnostic apparatus according to the sixth embodiment excludes the statistical value β except for pixels that tend to lower the calculated value of the statistical value β _{2. 2} is calculated. As a result, the X-ray condition is enhanced by the second ABC control in partial fluoroscopy, and it is possible to prevent an increase in the exposure dose of the subject.

[Seventh Embodiment]
Next, a medical image diagnostic apparatus according to the seventh embodiment will be described with reference to FIGS. In the seventh embodiment, the user interface 16, the collected data processing unit 15, and the X-ray control unit 12 are different from those in the first to sixth embodiments. Other parts are the same as those of the medical image diagnostic apparatus according to the first to sixth embodiments. Hereinafter, the difference from the sixth embodiment will be mainly described.

(Overview)
When calculating the statistical value β ₂ of the pixel value of the partial fluoroscopic image, the medical image diagnostic apparatus according to the seventh embodiment performs ABC control of the range selected by the operator's designation with respect to the displayed partial fluoroscopic image. I do. In the seventh embodiment, when the second ABC control is performed, for example, on the composite image display screen as illustrated in FIG. 3, the operator adjusts the brightness of the partial perspective image via the operation unit 162. You can specify the range you want to do. When a range for brightness adjustment is designated via the operation unit 162, the arithmetic control unit 11 receives position information of the designated range from the user interface 16. In addition, the calculation control unit 11 sends position information of the specified range to the pixel value calculation unit 153. The pixel value calculation unit 153 calculates a statistical value of pixel values within the specified range based on the position information from the calculation control unit 11. With such a configuration, it is possible to adjust the luminance within a range desired by the operator on the composite image.

(User interface 16)
The display unit 161 displays a combined image of the LIH image and the fluoroscopic image as shown in FIG. 3 in the partial fluoroscopy. The operator can designate a range on the partial perspective image of the displayed composite image via the operation unit 162 (for example, a pointing device such as a mouse). The range specified here is not limited to a rectangular shape, and any range can be specified. For example, the range may be designated according to the route of the point moved on the display screen in accordance with an operation using the operation unit 162. When the user interface 16 is configured to be directly operable on a display such as a touch panel, the user interface 16 receives a range designated directly on the display as input of position information.

Upon receiving the input of the designated range, the user interface 16 sends the determined position information to the arithmetic control unit 11. Note that the position information input by the user interface 16 may be a calculation range statistics beta ₂ of the pixel values of the partial fluoroscopic image may be in the range excluding. However, as the range designation operation, it is assumed that the designated range is selected as the calculation range or the exclusion range.

(Pixel value calculation unit 153)
The pixel value calculation unit 153 obtains the statistical value β ₁ as in the first embodiment. In addition, the pixel value calculation unit 153 according to the seventh embodiment receives, from the calculation control unit 11, the position information of the range that is the target of the calculation range or the position information of the range that is excluded from the calculation range, together with the image data of the partial perspective image. . Pixel value calculating unit 153, based on the position information, from all pixels of the partial fluoroscopic image, squeeze pixels to calculate as a statistical value beta ₂ of the pixel values, determining the statistical value beta _2. Incidentally, on the basis of the position information, from all pixels of the partial fluoroscopic image, the step of squeezing the pixels to calculate as a statistical value beta ₂ of the pixel values, may be performed by the calculation control unit 11.

(Other examples)
The pixel value calculation unit 153 is not limited to the configuration in which the statistical value β ₂ of the partial fluoroscopic image is obtained after narrowing down the pixels for which the statistical value β ₂ is calculated based on the position information of the specified range. For example, the average value of the statistical value beta ₂ from after the start of the partially transparent to date, may be applied to a pixel of the specified range (exclusive range from calculation target). Further, the pixel value calculation unit 153 obtains the statistical value β ₂ by replacing the pixel value of the specific pixel with the pixel value of another adjacent pixel based on the position information of the specific pixel received from the calculation control unit 11. May be.

(Partial perspective)
Next, with reference to FIG. 18 and FIG. 19, the flow of control of the X-ray control unit 12 regarding partial fluoroscopy in the seventh embodiment will be described. 18 and 19 are schematic flowcharts for explaining a second ABC control flow of the medical image diagnostic apparatus relating to partial fluoroscopy according to the seventh embodiment.

(S81)
Position information of the partial fluoroscopic region of interest R2 is sent to the aperture controller 13 and the pixel value calculator 153, and an instruction to start partial fluoroscopy is sent to the main controller 121.

(S82)
The aperture control unit 13 limits the X-ray irradiation field to a range corresponding to the partial fluoroscopic region of interest R2 based on the position information of the partial fluoroscopic region of interest R2. The fluoroscopic irradiation condition setting unit 18 sends the fluoroscopic irradiation conditions to the main control unit 121.

(S83)
The position information of the partial fluoroscopic region of interest R2 is sent from the fluoroscopic irradiation condition setting unit 18 to the pixel value calculation unit 153 in response to the aperture control unit 13 narrowing the X-ray irradiation field. The pixel value calculation unit 153 changes the range for which the statistical value is calculated to the partial fluoroscopic region of interest R2.

(S84)
Based on the fluoroscopic irradiation condition received from the fluoroscopic irradiation condition setting unit 18, the X-ray control unit 12 controls the high voltage generation unit 122 and the like, and X-rays are irradiated in the partial fluoroscopic region of interest R2.

(S85)
When the X-ray detection unit 5 generates detection data based on transmitted X-rays, the detection data is sent to the collected data processing unit 15. The collected data processing unit 15 temporarily stores the detection data in the storage unit 156. The image generation unit 152 reads detection data from the storage unit 156. Furthermore, the image generation unit 152 generates a partial perspective image.

(S86)
The user interface 16 determines whether or not there has been an operation for specifying a range by the operation unit 162 or the like and an operation for confirming the specified range for the partial perspective image in the displayed composite image.

(S87)
Also if there is the specified range (S86; Yes), the user interface 16, the range is based on the operation such as the operation unit 162 whether an exclusion range statistics beta ₂ of the pixel values of the pixels in the partial fluoroscopic image to decide.

(S88)
The user interface 16, if the determined specified range is determined to be in the range excluded from the calculation range of the statistical value β ₂ (S87; Yes), out of the partially transparent image, the positional information of the pixels excluding the specified range This is sent to the calculation control unit 11. Pixel value calculating unit 153 receives the position information via the arithmetic control unit 11 calculates a statistical value beta ₂ of the pixel values of the partially transparent image specified range is excluded.

(S89)
The user interface 16, if the determined specified range is determined to be in the range excluded from the calculation range of the statistical value β ₂ (S87; No), of the partial fluoroscopic image, calculates the position information of the pixels belonging to a specified range Send to control unit 11. Pixel value calculating unit 153 receives the position information via the operation control unit 11, among the partial fluoroscopic image to determine the statistics beta ₂ of the pixel values of the pixels belonging to a specified range.

(S90)
If no range is specified in S86 (S86; No), the user interface 16 does not send position information to the calculation control unit 11. The pixel value calculator 153 calculates the statistical value beta ₂ of the pixel values of all pixels in the partial fluoroscopic image.

(S91)
The pixel value comparison unit 154 compares the pixel value statistical value β ₂ obtained by the pixel value calculation unit 153 with the threshold value α ₁ received from the fluoroscopic irradiation condition setting unit 18. The pixel value comparison unit 154 may determine whether the comparison result is within a predetermined range.

(S92)
The pixel value comparison unit 154 (or the main control unit 121) refers to the comparison result by the pixel value comparison unit 154 and determines whether the difference (or ratio) between the statistical value β ₂ of the pixel value and the threshold value α ₁ is large. To determine whether to change the fluoroscopic irradiation conditions such as the X-ray conditions.

(S93)
Greater the difference between the statistical value beta ₂ and the threshold alpha ₁ pixel value (or ratio) of (S92; Yes), the main control unit 121 to change the parameters relating to the tube voltage kV, tube current, irradiation time product mAs.

(S94)
Further, if the difference (or ratio) between the pixel value statistical value β ₂ and the threshold value α ₁ is small (S92; No), the main control unit 121 maintains the fluoroscopic irradiation condition as it is.

(S95)
The main control unit 121 determines whether to continue the partial fluoroscopy. For example, when the operator gives an instruction to stop partial fluoroscopy via the operation unit 162, an X-ray irradiation stop instruction signal is sent to the main control unit 121 via the arithmetic control unit 11. The collected data processing unit 15 and the main control unit 121 sequentially repeat the operations of S84 to S93 until receiving the X-ray irradiation stop instruction signal. The process of S94 has been described as a subsequent process of S92 or S93 for convenience of explanation. However, if the main control unit 121 receives an X-ray irradiation stop instruction signal at any time of S84 to S91, at that time. The main control unit 121 stops the X-ray irradiation.

(Function and effect)
The operation and effect of the medical image diagnostic apparatus according to the seventh embodiment described above will be described.

  In the medical image diagnostic apparatus according to the present embodiment, when the fluoroscopy in the normal region of interest R1 is stopped and the fluoroscopy in the region of partial fluoroscopy R2 is started, the first ABC control is switched to the second ABC control. . That is, when partial fluoroscopy is started, the statistical value calculation range of the pixel values of the partial fluoroscopic image is made to correspond to the partial fluoroscopic region of interest R2. Therefore, it is possible to avoid a situation in which the statistical value becomes too low due to the calculation range of the statistical value to be subjected to ABC control exceeding the range of the partial fluoroscopic image. As a result, it is possible to prevent an increase in the exposure dose of the subject due to the X-ray condition being increased by the second ABC control in partial fluoroscopy.

  In addition, the medical image diagnostic apparatus according to the present embodiment is not limited to the case of partial fluoroscopy, and the calculation range of the statistical value of the pixel value corresponds to the fluoroscopy range even when the region of interest is unintentionally narrowed. Limit the area of interest. Therefore, it is possible to prevent an increase in the exposure dose of the subject due to unintentionally increasing the X-ray condition.

The pixels in the partial perspective image may include not only pixels within the range of the partial perspective region of interest R2 but also pixels within the range of the normal region of interest R1 and outside the range of the partial perspective region of interest R2. In addition, the partial fluoroscopic region of interest R2 may include a pixel group that indicates a structure such as a pacemaker or a bone that tends to have low luminance. In this regard, the medical image diagnostic apparatus in the seventh embodiment, in calculating the statistical value beta ₂ of the pixel values of the partial fluoroscopic image, calculates the statistical value beta ₂ of the pixel value range operator desires. As a result, it is possible to avoid a situation in which the X-ray condition is unnecessarily increased by the second ABC control in partial fluoroscopy, and thus it is possible to prevent an increase in the exposure dose of the subject.

[Eighth Embodiment]
Next, a medical image diagnostic apparatus according to the eighth embodiment will be described with reference to FIGS. FIG. 20 is a schematic block diagram showing the overall configuration of the X-ray imaging apparatus according to the eighth embodiment. The X-ray diagnostic apparatus 100A of the eighth embodiment shown in the figure includes a bed 2A, an X-ray tube 3A, an X-ray diaphragm 4A, and an X-ray detector 5A. However, these functions and actions are the same as those of the bed 2, the X-ray tube 3, the X-ray diaphragm 4 and the X-ray detection unit 5 shown in FIG. 1. The X-ray diagnostic apparatus 100A includes an arithmetic control unit 11A, an X-ray control unit 12A, an aperture control unit 13A, a drive control unit 14A, a collection data processing unit 15A, a user interface 16A, a display data processing unit 17A, and fluoroscopic irradiation conditions. A setting unit 18A is provided. Among these, the calculation control unit 11A, the aperture control unit 13A, the user interface 16A, and the display data processing unit 17A are the same as the calculation control unit 11, the aperture control unit 13, the user interface 16, and the display data processing unit 17 in the first embodiment. It is the composition.

(Overview)
The medical image diagnostic apparatus according to the eighth embodiment calculates a statistical value of a pixel value of a fluoroscopic image. In this calculation, the medical image diagnostic apparatus excludes pixels having a predetermined pixel value, for example, pixels having a pixel value less than the threshold value. Accordingly, the statistical value of the pixel value of the fluoroscopic image is calculated by excluding pixels that tend to lower the calculated value of the statistical value, for example, pixels indicating an artificial valve, a pacemaker, or the like. In other words, the statistical value of the pixel value is calculated by excluding a portion that tends to lower the luminance in the fluoroscopic image, and ABC control is performed.

<Collecting data processing unit 15A>
The collected data processing unit 15A performs various image processing and the like on the detection data to form an image (image data). The collected data processing unit 15A is an example of a function of an “X-ray image generation unit”.

<Fluoroscopic irradiation condition setting unit 18A>
The fluoroscopic irradiation condition setting unit 18A receives an input from the operation unit 162A via the calculation control unit 11A, and based on the input, the fluoroscopic irradiation condition such as the X-ray condition and the region of interest (ROI) position information, and detection data Set the collection conditions. For example, in the setting of fluoroscopic irradiation conditions for fluoroscopy, when the operator sets the tube voltage kV according to the body thickness of the subject or the imaging region, the fluoroscopic irradiation condition setting unit 18 responds accordingly by the tube current / irradiation time product mAs. Set. The set fluoroscopic irradiation conditions and detection data collection conditions are sent to the X-ray control unit 12A and the aperture control unit 13A via the calculation control unit 11A.

The fluoroscopic irradiation condition setting unit 18A, from the operation unit 162A via the operation control unit 11A, receives an input of threshold alpha ₁ for use in the ABC control. Fluoroscopy radiation condition setting unit 18A stores a threshold value alpha _1. When the collected data processing unit 15A is ABC control is performed, fluoroscopic irradiation condition setting unit 18A sends the threshold value alpha ₁ inputted, the collection data processing section 15A through the operation control unit 11A. Input threshold alpha ₁ may be preset to fluoroscopic irradiation condition setting unit 18A, or may be set in response to the execution of the shooting. This threshold value α ₁ is a threshold value for comparison with the statistical value β of the pixel value of the X-ray image, which is obtained by the pixel value calculation unit 153A. Examples of the statistical value of the pixel value include an average value, an intermediate value, a standard deviation, a minimum value, and a maximum value of the pixel values. The threshold value is set according to the statistical value calculation method.

Also as in the fifth embodiment, fluoroscopy irradiation condition setting unit 18A, from the operation unit 162A via the operation control unit 11A, receives the threshold alpha ₁ and the threshold alpha _2, and stores them.

  Further, the fluoroscopic irradiation condition setting unit 18A receives the information on the region of interest from the operation unit 162A via the calculation control unit 11A. For example, when a region of interest is set by an operator's operation on the fluoroscopic irradiation condition setting screen, position information of these regions of interest is received from the operation unit 162A via the arithmetic control unit 11A. This position information is set as an imaging range by the fluoroscopic irradiation condition setting unit 18A.

(ABC control of the collected data processing unit 15A)
Next, threshold processing and ABC control of the collected data processing unit 15A in the X-ray imaging apparatus will be described. The configuration of the collected data processing unit 15A is the same as the configuration of the collected data processing unit 15 according to the first embodiment.

  For example, the image generation unit 152A generates an X-ray image based on the detection data, similarly to the image generation unit 152 of the first embodiment. Further, the pixel value calculation unit 153A obtains a statistical value (average value, intermediate value, etc.) β of pixel values in an X-ray image such as a fluoroscopic image, similarly to the pixel value calculation unit 153 of the first embodiment. The storage unit 156 stores each X-ray image.

The collected data processing unit 15A performs threshold processing and ABC control as in the fifth embodiment. Collecting data processing unit 15A receives the information of the threshold value alpha ₁ and the threshold alpha ₂ of preset luminance from fluoroscopy irradiation condition setting unit 18A.

<Threshold processing by the threshold α _2>
Pixel value comparison unit 154A receives data fluoroscopic image from the image generator 152, also receives information threshold alpha ₂ from fluoroscopy irradiation condition setting unit 18. Further pixel value comparison unit 154A compares the pixel value and the threshold value alpha ₂ of each pixel in the fluoroscopic image. The pixel value comparison unit 154A, for example among the pixels, identifying a pixel having a pixel value smaller than the threshold value alpha ₂ (or the threshold alpha ₂ below). Further, the pixel value comparison unit 154A sends the partial perspective image data together with the specified pixel position information to the pixel value calculation unit 153A.

Pixel value calculation unit 153A, among the pixels of the partially transparent image, on the basis of the position information received from the pixel value comparison unit 154A, except for the pixels having pixel values less than the threshold alpha ₂ (or the threshold alpha ₂ below) The statistical value β ₂ is obtained. Pixel value calculation unit 153A sends statistics beta ₂ which thus obtains the pixel value comparison unit 154A. Pixel value comparison unit 154A compares the statistical value beta ₂ and the threshold alpha _1, and sends the comparison result to the X-ray control unit 12A. Specific processing by the pixel value comparison unit 154A is as follows.

<Threshold processing by the threshold α _1>
The pixel value comparison unit 154A receives information on the threshold value α of the pixel value from the fluoroscopic irradiation condition setting unit 18A. The pixel value comparison unit 154A receives information statistics β pixel values calculated by the pixel value calculation unit 153A, it is compared with the threshold value alpha _1. Further, the fluoroscopic irradiation conditions are adjusted based on the comparison result. The pixel value comparison unit 154A may be configured to send the comparison result to the main control unit 121A. In this case, the main control unit 121A adjusts the fluoroscopic irradiation conditions based on the comparison result. Note that the result of the comparison and is referred, for example, the threshold value alpha ₁ and may be information indicating a difference between the statistic β of the pixel value, or may be information indicating a ratio.

Further pixel value comparison unit 154A, the difference or the ratio between the threshold alpha ₁ and statistics β may be determined whether it is within a predetermined range. In this example, if the difference is within a predetermined range, the pixel value comparison unit 154A determines that the change of the X-ray condition is unnecessary, and does not send the comparison result to the main control unit 121A. If the difference is outside the predetermined range, the comparison result, that is, the difference is sent to the main control unit 121. The main control unit 121A adjusts the X-ray condition according to this difference or the like. Further, the X-ray irradiation condition may be adjusted by the pixel value comparison unit 154A sending the adjusted X-ray irradiation condition based on the comparison result.

<X-ray controller 12A-high voltage generator 122A>
The main controller 121A controls the high voltage generator 122A to apply a high voltage necessary for X-ray irradiation to the X-ray tube 3A. The high voltage generator 122A and the control thereof are the same as in the first embodiment. In addition, the X-ray control unit 12A performs control related to X-ray irradiation in response to the adjusted fluoroscopic irradiation conditions according to ABC control by the collected data processing unit 15A. The specific control contents of the collected data processing unit 15A will be described later.

  In addition, when the operator performs an operation to interrupt fluoroscopic imaging by the operation unit 162A, an X-ray irradiation stop instruction signal is sent from the arithmetic control unit 11A to the main control unit 121A. In response to the signal, the main control unit 121A stops driving the units related to the X-ray irradiation (output) such as the high voltage generation unit 122A, and stops the X-ray irradiation.

  Thus, the collected data processing unit 15 obtains the statistical value β of the luminance (pixel value) in the current fluoroscopic image in ABC control. The collected data processing unit 15A further compares the threshold value α with the statistical value β. The collected data processing unit 15 reflects the result of the comparison in fluoroscopic irradiation conditions such as the X-ray conditions (tube voltage kV, tube current / irradiation time product mAs) in the X-ray control unit 12. Note that the fluoroscopic irradiation condition corresponds to an example of “operation condition of photographing unit”.

(Operation)
Next, the flow of control and processing in the medical image diagnostic apparatus of the eighth embodiment will be described with reference to FIGS. FIG. 21 and FIG. 22 are schematic flowcharts for explaining the flow of ABC control of the medical image diagnostic apparatus in the eighth embodiment.

(S101)
The fluoroscopic irradiation condition setting unit 18A sends the fluoroscopic irradiation condition to the main control unit 121A.

(S102)
Based on the fluoroscopic irradiation conditions received from the fluoroscopic irradiation condition setting unit 18A, the X-ray control unit 12A controls the high voltage generator 122A and the like, and X-rays are irradiated.

(S103)
When the X-ray detection unit 5A generates detection data based on transmitted X-rays, the detection data is sent to the collected data processing unit 15A. The collected data processing unit 15A temporarily stores the detection data in the storage unit 156A. The image generation unit 152A reads detection data from the storage unit 156A. Furthermore, the image generation unit 152A generates a perspective image.

(S104)
Pixel value comparison unit 154A compares the pixel value of each pixel in the fluoroscopic image with the threshold alpha _2. In one example, the pixel value comparison unit 154A, out of the pixels, identifying a pixel having a pixel value smaller than the threshold value alpha ₂ (or the threshold alpha ₂ below). Further, the pixel value comparison unit 154A sends the fluoroscopic image data together with the specified position information of the pixel to the pixel value calculation unit 153A. That is, the pixels other than the pixel specified by the pixel value comparison unit 154A are the calculation target of the statistical value β.

(S105)
Pixel value calculation unit 153A in one example, except for the pixels having pixel values less than the threshold alpha ₂ (or the threshold alpha ₂ below) obtaining a statistical value beta.

(S106)
Pixel value comparison unit 154A compares the statistical value β of the pixel values calculated by the pixel value calculation unit 153A, a threshold value alpha ₁ received from the fluoroscopic irradiation conditions setting unit 18A. Note that the pixel value comparison unit 154A may determine whether the comparison result is within a predetermined range.

(S107)
Pixel value comparison unit 154A (or the main control unit 121A), by reference to the comparison result by the pixel value comparison unit 154A, it is determined whether the difference between the statistical value β and the threshold alpha ₁ pixel value (or ratio) is large It is determined whether to change fluoroscopic irradiation conditions such as X-ray conditions.

(S108)
Greater the difference between the statistical value β and the threshold alpha ₁ pixel value (or ratio) of (S107; Yes), the main control unit 121 to change the parameters relating to the tube voltage kV, tube current, irradiation time product mAs.

(S109)
The main control unit 121A, if the difference is small (or the ratio) between the statistical value β and the threshold alpha ₁ pixel value (S107; No), the main control unit 121A maintains intact the fluoroscopic irradiation conditions.

(S110)
The main control unit 121A determines whether to continue fluoroscopy. For example, when the operator gives an instruction to stop partial fluoroscopy via the operation unit 162A, an X-ray irradiation stop instruction signal is sent to the main control unit 121A via the arithmetic control unit 11A. The main control unit 121A sequentially repeats the operations of S101 to S109 until receiving the X-ray irradiation stop instruction signal. The process of S110 has been described as a subsequent process of S108 or S109 for convenience of explanation. However, when the main control unit 121A receives an X-ray irradiation stop instruction signal at any time point of S101 to S106, at that time point. The main controller 121A stops X-ray irradiation.

(Function and effect)
The operation and effect of the medical image diagnostic apparatus according to the eighth embodiment described above will be described.

  The pixels in the fluoroscopic image may include pixels outside the region of interest (such as a portion hitting the aperture blade). In addition, the region of interest may include a pixel group indicating a structure such as a pacemaker or a bone that tends to have low luminance. In this regard, when calculating the statistical value β of the pixel value, the medical image diagnostic apparatus according to the eighth embodiment calculates the statistical value β except for pixels that tend to lower the calculated value of the statistical value β. As a result, the X-ray conditions are enhanced by ABC control, and it is possible to prevent an increase in the exposure dose of the subject.

[Ninth Embodiment]
Next, a medical image diagnostic apparatus according to the ninth embodiment will be described with reference to FIGS. FIG. 23 is a schematic block diagram illustrating a part of the functional configuration of the collected data processing unit 15A according to the ninth embodiment. The ninth embodiment differs from the eighth embodiment in the collected data processing unit 15A and the X-ray control unit 12A. The processing contents of the medical image diagnostic apparatus are the same as in the sixth embodiment. Other parts are the same as those of the medical image diagnostic apparatus according to the eighth embodiment. Hereinafter, the difference from the eighth embodiment will be mainly described.

(Overview)
In calculating the statistical value β, the medical image diagnostic apparatus according to the ninth embodiment performs pattern recognition of each portion indicated in the fluoroscopic image. About pattern recognition, it is the same as that of 6th Embodiment. Thereby, the statistical value of the pixel value of the fluoroscopic image is calculated except for the range (pixel group) that tends to lower the calculated value of the statistical value β. In other words, the statistical value β of the pixel value is calculated by excluding a portion that tends to lower the luminance in the fluoroscopic image, and ABC control is performed.

(Storage unit 156A)
The storage unit 156A in the collected data processing unit 15A stores the same pattern as the storage unit 156A in the sixth embodiment.

(Comparator 159)
The collected data processing unit 15A in the ninth embodiment is the same as the collected data processing unit 15 in the sixth embodiment shown in FIG. That is, it includes an interface 151A, an image generation unit 152A, a pixel value calculation unit 153A, a pixel value comparison unit 154A, a first gain adjustment unit 155A, and a comparison unit 159A (see FIG. 23).

The comparison unit 159A receives the image data generated by the image generation unit 152A, and extracts each pixel group constituting the perspective image.
The comparison unit 159A may extract each pixel group from the image data adjusted by the image adjustment unit 173A. For example, the collected data processing unit 15A sends image data different from the partial fluoroscopic image to be a composite image to the image adjusting unit 173A. The image adjustment unit 173A performs processing such as noise reduction, edge detection, and contour enhancement. The comparison unit 159A extracts the outline of each pixel group indicated in the processed partial fluoroscopic image. Since this partial perspective image is different from the display mode on the display unit 161A, the contour extraction can be more emphasized without considering the visibility of the image.

  The comparison unit 159A extracts each pixel group whose outline is emphasized. The comparison unit 159A reads the specific structure pattern from the storage unit 156A, and compares the specific structure pattern with the specific structure pattern for each extracted pixel group. The comparison unit 159A determines whether these are correlated as a result of the comparison. As an example, the comparison unit 159 first extracts feature points of the pixel group extracted from the perspective image. The feature point of the structure is a feature point in the contour shape of the structure. This feature point is collated with the read specific structure pattern.

  As another example, the comparison unit 159A may collate whether the outline of each pixel group in the partial perspective image correlates with the specific structure pattern.

  In any case, if the specific structure pattern stored in the storage unit 156A is three-dimensional, the comparison unit 159A determines each pixel group (two-dimensional image) of the perspective image as a three-dimensional specific structure. Matching is performed for each detection angle and detection direction with respect to the object pattern.

  As a result of the collation, the comparison unit 159A obtains the degree of similarity, the degree of correlation, the matching rate, and the like between each pixel group in the partial perspective image and the specific structure pattern. As a result of the pattern recognition, if the similarity between the specific structure pattern and the pixel group is equal to or greater than a preset value, the comparison unit 159A selects the pixel group in the partial perspective image as a structure ( For example, a pacemaker).

  When the comparison unit 159A determines that the pixel group indicated by the partial perspective image corresponds to the specific structure pattern stored in advance, the comparison unit 159A specifies the pixels in the range occupied by the pixel group of the partial perspective image. Further, the comparison unit 159A excludes the specified range of pixels from the entire partial perspective image, and then sends the partial perspective image data to the pixel value calculation unit 153A.

(Pixel value calculation unit 153A)
The pixel value calculation unit 153A obtains the statistical value β of the fluoroscopic image from which the pixels in the predetermined range are removed by the comparison unit 159A as described above.

(Other examples)
Note that the pixel value calculation unit 153A may perform the step of excluding a predetermined range of pixels by the pixel value calculation unit 153A. That is, the comparison unit 159A obtains a pixel group of a fluoroscopic image corresponding to the specific structure pattern, and specifies position information (coordinates in the fluoroscopic image, etc.) of a range occupied by the pixel group. Further, the comparison unit 159A sends the specified position information and fluoroscopic image data to the pixel value calculation unit 153A. In this configuration, the pixel value calculation unit 153A determines the statistical value β by excluding a predetermined range of pixels based on the received position information.

  Further, the pixel value calculation unit 153A may obtain the statistical value β by replacing the pixel value of the specific pixel with the pixel value of another adjacent pixel based on the position information of the specific pixel received from the comparison unit 159A. Good.

(Operation)
Next, with reference to FIG. 24 and FIG. 25, the flow of control and processing in the medical image diagnostic apparatus of the ninth embodiment will be described. 24 and 25 are schematic flowcharts for explaining the flow of ABC control of the medical image diagnostic apparatus according to the ninth embodiment.

(S121)
The fluoroscopic irradiation condition setting unit 18A sends the fluoroscopic irradiation condition to the main control unit 121A.

(S122)
Based on the fluoroscopic irradiation conditions received from the fluoroscopic irradiation condition setting unit 18A, the X-ray control unit 12A controls the high voltage generator 122A and the like, and X-rays are irradiated.

(S123)
When the X-ray detection unit 5A generates detection data based on transmitted X-rays, the detection data is sent to the collected data processing unit 15A. The collected data processing unit 15A temporarily stores the detection data in the storage unit 156A. The image generation unit 152A reads detection data from the storage unit 156A. Furthermore, the image generation unit 152A generates a perspective image.

(S124)
In one example, the comparison unit 159A extracts a pixel group from the perspective image.

(S125)
As an example, the comparison unit 159A extracts feature points of the pixel group extracted from the perspective image. The feature point of the structure is a feature point in the contour shape of the structure. This feature point is collated with the read specific structure pattern.

(S126)
As a result of the collation, the comparison unit 159A determines whether the similarity between each pixel group in the perspective image and the specific structure pattern is equal to or greater than a preset value. If the similarity or the like is equal to or greater than the set value, the pixel group in the perspective image is determined as a structure (for example, a pacemaker) related to the specific structure pattern.

(S127)
As an example, if the comparison unit 159A determines that the pixel group indicated by the perspective image corresponds to the specific structure pattern stored in advance (S126; Yes), the comparison unit 159A specifies pixels in a range occupied by the pixel group of the perspective image. Further, the comparison unit 159A excludes the specified range of pixels from the entire fluoroscopic image, and sends the data of the fluoroscopic image to the pixel value calculation unit 153A.

(S128)
The comparison unit 159A excludes the specified range of pixels from the entire fluoroscopic image, and sends the fluoroscopic image data to the pixel value calculation unit 153A. If the comparison unit 159A determines that all of the pixel groups indicated by the perspective image do not correspond to the specific structure pattern stored in advance (S126; No), the comparison unit 159A sends the image data of the perspective image to the pixel value calculation unit 153A as it is. The pixel value calculation unit 153A obtains a statistical value β of the pixel value of the pixel in any of the above-described perspective images.

(S129)
Pixel value comparison unit 154A compares the statistical value β of the pixel values calculated by the pixel value calculation unit 153A, a threshold value alpha ₁ received from the fluoroscopic irradiation conditions setting unit 18A. Note that the pixel value comparison unit 154A may determine whether the comparison result is within a predetermined range.

(S130)
Pixel value comparison unit 154A (or the main control unit 121A), by reference to the comparison result by the pixel value comparison unit 154A, it is determined whether the difference between the statistical value β and the threshold alpha ₁ pixel value (or ratio) is large It is determined whether to change fluoroscopic irradiation conditions such as X-ray conditions.

(S131)
If the difference between the statistical value β and the threshold alpha ₁ pixel value (or ratio) is large (S130; Yes), the main control unit 121A changes the parameters relating to the tube voltage kV, tube current, irradiation time product mAs.

(S132)
The main control unit 121A, if the difference is small (or Hi) of the statistic β and the threshold alpha ₁ pixel value (S130; No), the main control unit 121A maintains unaltered a perspective irradiation conditions.

(S133)
The main control unit 121A determines whether to continue fluoroscopy. For example, when the operator gives an instruction to stop fluoroscopy via the operation unit 162A, an X-ray irradiation stop instruction signal is sent to the main control unit 121A via the arithmetic control unit 11A. The collected data processing unit 15A and the main control unit 121A sequentially repeat the operations of S122 to S132 until receiving the X-ray irradiation stop instruction signal. Note that the process of S133 has been described as a subsequent process of S131 or S132 for convenience of explanation. However, if the main control unit 121A receives an X-ray irradiation stop instruction signal at any time point of S122 to S130, at that time point. The main controller 121A stops X-ray irradiation.

(Function and effect)
The operation and effect of the medical image diagnostic apparatus according to the ninth embodiment described above will be described.

  The pixels in the fluoroscopic image may include pixels outside the region of interest (such as a portion hitting the aperture blade). In addition, the region of interest may include a pixel group indicating a structure such as a pacemaker or a bone that tends to have low luminance. In this regard, when calculating the statistical value β of the pixel value, the medical image diagnostic apparatus according to the ninth embodiment calculates the statistical value β except for pixels that tend to lower the calculated value of the statistical value β. As a result, the X-ray conditions are enhanced by ABC control, and it is possible to prevent an increase in the exposure dose of the subject.

[Tenth embodiment]
Next, a medical image diagnostic apparatus according to the tenth embodiment will be described. The tenth embodiment is different from the eighth embodiment in the user interface 16A, the collected data processing unit 15A, and the X-ray control unit 12A. The processing contents of the medical image diagnostic apparatus are the same as those in the seventh embodiment. Other parts are the same as those of the medical image diagnostic apparatus according to the eighth embodiment. Hereinafter, the difference from the eighth embodiment will be mainly described.

(Overview)
The medical image diagnostic apparatus according to the tenth embodiment performs ABC control of a range selected by the operator in the fluoroscopic image when calculating the statistical value β. In the tenth embodiment, when ABC control is performed, for example, an operator can designate a range in which brightness adjustment is desired for a fluoroscopic image. When the range is designated, the arithmetic control unit 11A receives position information of the designated range from the user interface 16A. In addition, the calculation control unit 11A sends position information of the specified range to the pixel value calculation unit 153A. The pixel value calculation unit 153A calculates a statistical value of pixel values within the specified range based on the position information from the calculation control unit 11A. With such a configuration, it is possible to adjust the luminance within a range desired by the operator on the image.

(User interface 16A)
The operator can specify a range on the displayed fluoroscopic image via the operation unit 162A. The range specified here is not limited to a rectangular shape, and any range can be specified.

  In response to the input of the specified range, the user interface 16A sends the determined position information to the arithmetic control unit 11A. Note that the position information input by the user interface 16A may be a calculation range of the statistical value β or a range to be excluded. However, as the range designation operation, it is assumed that the designated range is selected as the calculation range or the exclusion range.

(Pixel value calculation unit 153A)
The pixel value calculation unit 153A receives from the calculation control unit 11 image data and position information of a range to be calculated or excluded from the calculation range. Based on the position information, the pixel value calculation unit 153A narrows down the pixels to be calculated as the statistical value β from all the pixels to obtain the statistical value β. Note that the step of narrowing down the pixels calculated as the statistical value β of the pixel values from all the pixels may be performed by the arithmetic control unit 11.

(Other examples)
Note that the pixel value calculation unit 153A may apply the average value of the statistical value β from the start of fluoroscopy to the present time to pixels in the specified range (exclusion range from the calculation target). Further, the pixel value calculation unit 153A obtains the statistical value β by replacing the pixel value of the specific pixel with the pixel value of another adjacent pixel based on the position information of the specific pixel received from the calculation control unit 11A. Also good.

(Operation)
Next, a control flow of the X-ray control unit 12A regarding fluoroscopy in the tenth embodiment will be described with reference to FIGS. 26 and 27. FIG. 26 and 27 are schematic flowcharts for explaining the flow of ABC control of the medical image diagnostic apparatus relating to fluoroscopy in the tenth embodiment.

(S141)
Position information of the region of interest is sent to the aperture controller 13A and the pixel value calculator 153A, and an instruction to start fluoroscopy is sent to the main controller 121A.

(S142)
The fluoroscopic irradiation condition setting unit 18A sends the fluoroscopic irradiation condition to the main control unit 121A.

(S143)
Based on the fluoroscopic irradiation conditions received from the fluoroscopic irradiation condition setting unit 18A, the X-ray control unit 12A controls the high voltage generator 122A and the like, and X-rays are irradiated.

(S144)
When the X-ray detection unit 5A generates detection data based on transmitted X-rays, the detection data is sent to the collected data processing unit 15A. The collected data processing unit 15A temporarily stores the detection data in the storage unit 156A. The image generation unit 152A reads detection data from the storage unit 156A. Furthermore, the image generation unit 152A generates a perspective image.

(S145)
The user interface 16A determines whether or not there has been an operation for specifying a range by the operation unit 162A or the like and an operation for confirming the specified range for the displayed fluoroscopic image.

(S146)
When the range is designated (S145; Yes), the user interface 16A determines whether the range is an excluded range of the pixel value statistical value β of the pixel in the fluoroscopic image based on the operation of the operation unit 162A or the like. .

(S147)
When the user interface 16A determines that the determined designated range is excluded from the calculation range of the statistical value β (S146; Yes), the position information of the pixels excluding the designated range in the fluoroscopic image is arithmetically controlled. Send to part 11A. The pixel value calculation unit 153A receives the position information via the calculation control unit 11A, and obtains the statistical value β of the pixel value of the fluoroscopic image excluding the designated range.

(S148)
When the user interface 16A determines that the determined designated range is a range to be excluded from the calculation range of the statistical value β (S146; No), the position information of pixels belonging to the designated range in the fluoroscopic image is calculated and controlled. Send to 11A. The pixel value calculation unit 153A receives the position information via the calculation control unit 11A, and obtains the statistical value β of the pixel value of the pixel belonging to the specified range in the perspective image.

(S149)
If it is determined in S145 that the range is not specified (S145; No), the user interface 16A does not send the position information to the calculation control unit 11. Further, the pixel value calculation unit 153A obtains a statistical value β of the pixel values of all the pixels in the perspective image.

(S150)
Pixel value comparison unit 154A compares the statistical value β of the pixel values calculated by the pixel value calculation unit 153A, a threshold value alpha ₁ received from the fluoroscopic irradiation conditions setting unit 18A. Note that the pixel value comparison unit 154A may determine whether the comparison result is within a predetermined range.

(S151)
Pixel value comparison unit 154A (or the main control unit 121A), by reference to the comparison result by the pixel value comparison unit 154A, it is determined whether the difference between the statistical value β and the threshold alpha ₁ pixel value (or ratio) is large It is determined whether to change fluoroscopic irradiation conditions such as X-ray conditions.

(S152)
If the difference between the statistical value β and the threshold alpha ₁ pixel value (or ratio) is large (S151; Yes), the main control unit 121A changes the parameters relating to the tube voltage kV, tube current, irradiation time product mAs.

(S153)
The main control unit 121A, if the difference is small (or the ratio) between the statistical value β and the threshold alpha ₁ pixel value (S151; No), the main control unit 121A maintains intact the fluoroscopic irradiation conditions.

(S154)
The main control unit 121A determines whether to continue fluoroscopy. For example, when the operator gives an instruction to stop fluoroscopy via the operation unit 162A, an X-ray irradiation stop instruction signal is sent to the main control unit 121A via the arithmetic control unit 11A. The collected data processing unit 15A and the main control unit 121A sequentially repeat the operations of S144 to S153 until receiving the X-ray irradiation stop instruction signal. Note that the processing of S154 has been described as a subsequent process of S152 or S153 for convenience of explanation, but when the main control unit 121A receives an X-ray irradiation stop instruction signal at any time of S144 to S151, at that time The main controller 121A stops X-ray irradiation.

(Function and effect)
The operation and effect of the medical image diagnostic apparatus according to the tenth embodiment described above will be described.

  The pixels in the fluoroscopic image may include pixels outside the region of interest (such as a portion hitting the aperture blade). In addition, the region of interest may include a pixel group indicating a structure such as a pacemaker or a bone that tends to have low luminance. In this regard, the medical image diagnostic apparatus according to the tenth embodiment calculates the statistical value β of the pixel value in the range desired by the operator when calculating the statistical value β of the pixel value. As a result, the X-ray conditions are enhanced by ABC control, and it is possible to prevent an increase in the exposure dose of the subject.

[Combination of Embodiments]
The medical image diagnostic apparatuses of the first embodiment to the tenth embodiment described above can be appropriately combined. By appropriately combining the above-described embodiments, it is possible to more reliably both reduce the exposure amount of the subject and prevent the visibility of the fluoroscopic image and the partial fluoroscopic image from being lowered.

[Application to other devices]
In addition, the above-described first to tenth embodiments and combinations thereof are applicable not only to X-ray imaging apparatuses but also to X-ray CT apparatuses.

  Although the embodiment of the present invention has been described, the above-described embodiment has been presented as an example, and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 X-ray diagnostic apparatus 11 Calculation control part 12 X-ray control part 121 Main control part 122 High voltage generation part 13 Aperture control part 14 Drive control part 15 Collected data processing part 151 Interface 152 Image generation part 153 Pixel value calculation part 154 Pixel value Comparison unit 155 First gain adjustment unit 156 Storage unit 159 Comparison unit 172 Subtraction processing unit 173 Image adjustment unit 174 Image composition unit 175 Second gain adjustment unit 16 User interface 161 Display unit 162 Operation unit 18 Perspective irradiation condition setting unit 53 Projection data Generation unit 531 Charge / voltage converter 532 A / D converter 533 Parallel / serial converter R1 Region of interest R2 Region of interest for partial fluoroscopy T Target region

Claims (4)

An imaging unit capable of repeatedly imaging the subject by changing the X-ray irradiation range;
An X-ray image generation unit that generates an X-ray image based on the imaging;
A first storage unit that stores a first threshold value that is a threshold value of a pixel value set in advance;
A calculation unit that calculates a statistical value of the pixel value of the X-ray image and reduces the range of the pixel for which the statistical value is calculated in response to the reduction when the X-ray irradiation range is reduced in the imaging When,
An adjustment unit that adjusts an operation condition of the photographing unit so that the statistical value approaches the first threshold;
A second storage unit that stores a second threshold value that is a threshold value of a preset pixel value;
A comparison unit that identifies the some pixels so as to exclude pixels having low pixel values based on the second threshold;
With
The medical image diagnostic apparatus, wherein the calculation unit calculates the second statistical value for the part of pixels specified by the comparison unit. The imaging unit includes a first imaging for imaging a subject in a first X-ray irradiation range, and a second X-ray irradiation range that is narrower than the first X-ray irradiation range after the first imaging. Performing a second imaging in which the subject is repeatedly imaged,
The X-ray image generation unit generates a first X-ray image in the first X-ray irradiation range based on the first imaging, and the second X-ray irradiation based on the second imaging. Repeatedly generate a second X-ray image in the range;
A synthesis unit that repeatedly generates a combined image obtained by combining the first X-ray image and the second X-ray image with the repeated generation of the second X-ray image; The medical image diagnostic apparatus according to claim 1, wherein The medical image diagnostic apparatus according to claim 1, wherein the comparison unit specifies the some pixels by excluding pixel values that are less than or less than the second threshold value. An imaging unit capable of repeatedly imaging a subject;
An X-ray image generation unit that generates an X-ray image based on the imaging;
A first storage unit that stores a first threshold value that is a threshold value of a pixel value set in advance;
A calculation unit that calculates a statistical value of a part of pixel values of the X-ray image;
An adjustment unit that adjusts an operation condition of the photographing unit so that the statistical value approaches the first threshold;
A second storage unit for storing a pattern of a shape of a preset structure;
A comparison unit that identifies pixels corresponding to the structure correlated with the pattern among the structures indicated by the X-ray image, and identifies the partial pixels so as to exclude pixels corresponding to the structure; ,
With
The medical image diagnostic apparatus, wherein the calculation unit calculates the statistical value for the some pixels.

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